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Merge tag 'tpmdd-next-20160902' into next
[deliverable/linux.git] / fs / btrfs / relocation.c
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34
35 /*
36 * backref_node, mapping_node and tree_block start with this
37 */
38 struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41 };
42
43 /*
44 * present a tree block in the backref cache
45 */
46 struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85 };
86
87 /*
88 * present a block pointer in the backref cache
89 */
90 struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93 };
94
95 #define LOWER 0
96 #define UPPER 1
97 #define RELOCATION_RESERVED_NODES 256
98
99 struct backref_cache {
100 /* red black tree of all backref nodes in the cache */
101 struct rb_root rb_root;
102 /* for passing backref nodes to btrfs_reloc_cow_block */
103 struct backref_node *path[BTRFS_MAX_LEVEL];
104 /*
105 * list of blocks that have been cowed but some block
106 * pointers in upper level blocks may not reflect the
107 * new location
108 */
109 struct list_head pending[BTRFS_MAX_LEVEL];
110 /* list of backref nodes with no child node */
111 struct list_head leaves;
112 /* list of blocks that have been cowed in current transaction */
113 struct list_head changed;
114 /* list of detached backref node. */
115 struct list_head detached;
116
117 u64 last_trans;
118
119 int nr_nodes;
120 int nr_edges;
121 };
122
123 /*
124 * map address of tree root to tree
125 */
126 struct mapping_node {
127 struct rb_node rb_node;
128 u64 bytenr;
129 void *data;
130 };
131
132 struct mapping_tree {
133 struct rb_root rb_root;
134 spinlock_t lock;
135 };
136
137 /*
138 * present a tree block to process
139 */
140 struct tree_block {
141 struct rb_node rb_node;
142 u64 bytenr;
143 struct btrfs_key key;
144 unsigned int level:8;
145 unsigned int key_ready:1;
146 };
147
148 #define MAX_EXTENTS 128
149
150 struct file_extent_cluster {
151 u64 start;
152 u64 end;
153 u64 boundary[MAX_EXTENTS];
154 unsigned int nr;
155 };
156
157 struct reloc_control {
158 /* block group to relocate */
159 struct btrfs_block_group_cache *block_group;
160 /* extent tree */
161 struct btrfs_root *extent_root;
162 /* inode for moving data */
163 struct inode *data_inode;
164
165 struct btrfs_block_rsv *block_rsv;
166
167 struct backref_cache backref_cache;
168
169 struct file_extent_cluster cluster;
170 /* tree blocks have been processed */
171 struct extent_io_tree processed_blocks;
172 /* map start of tree root to corresponding reloc tree */
173 struct mapping_tree reloc_root_tree;
174 /* list of reloc trees */
175 struct list_head reloc_roots;
176 /* size of metadata reservation for merging reloc trees */
177 u64 merging_rsv_size;
178 /* size of relocated tree nodes */
179 u64 nodes_relocated;
180 /* reserved size for block group relocation*/
181 u64 reserved_bytes;
182
183 u64 search_start;
184 u64 extents_found;
185
186 unsigned int stage:8;
187 unsigned int create_reloc_tree:1;
188 unsigned int merge_reloc_tree:1;
189 unsigned int found_file_extent:1;
190 };
191
192 /* stages of data relocation */
193 #define MOVE_DATA_EXTENTS 0
194 #define UPDATE_DATA_PTRS 1
195
196 static void remove_backref_node(struct backref_cache *cache,
197 struct backref_node *node);
198 static void __mark_block_processed(struct reloc_control *rc,
199 struct backref_node *node);
200
201 static void mapping_tree_init(struct mapping_tree *tree)
202 {
203 tree->rb_root = RB_ROOT;
204 spin_lock_init(&tree->lock);
205 }
206
207 static void backref_cache_init(struct backref_cache *cache)
208 {
209 int i;
210 cache->rb_root = RB_ROOT;
211 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
212 INIT_LIST_HEAD(&cache->pending[i]);
213 INIT_LIST_HEAD(&cache->changed);
214 INIT_LIST_HEAD(&cache->detached);
215 INIT_LIST_HEAD(&cache->leaves);
216 }
217
218 static void backref_cache_cleanup(struct backref_cache *cache)
219 {
220 struct backref_node *node;
221 int i;
222
223 while (!list_empty(&cache->detached)) {
224 node = list_entry(cache->detached.next,
225 struct backref_node, list);
226 remove_backref_node(cache, node);
227 }
228
229 while (!list_empty(&cache->leaves)) {
230 node = list_entry(cache->leaves.next,
231 struct backref_node, lower);
232 remove_backref_node(cache, node);
233 }
234
235 cache->last_trans = 0;
236
237 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
238 ASSERT(list_empty(&cache->pending[i]));
239 ASSERT(list_empty(&cache->changed));
240 ASSERT(list_empty(&cache->detached));
241 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
242 ASSERT(!cache->nr_nodes);
243 ASSERT(!cache->nr_edges);
244 }
245
246 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
247 {
248 struct backref_node *node;
249
250 node = kzalloc(sizeof(*node), GFP_NOFS);
251 if (node) {
252 INIT_LIST_HEAD(&node->list);
253 INIT_LIST_HEAD(&node->upper);
254 INIT_LIST_HEAD(&node->lower);
255 RB_CLEAR_NODE(&node->rb_node);
256 cache->nr_nodes++;
257 }
258 return node;
259 }
260
261 static void free_backref_node(struct backref_cache *cache,
262 struct backref_node *node)
263 {
264 if (node) {
265 cache->nr_nodes--;
266 kfree(node);
267 }
268 }
269
270 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
271 {
272 struct backref_edge *edge;
273
274 edge = kzalloc(sizeof(*edge), GFP_NOFS);
275 if (edge)
276 cache->nr_edges++;
277 return edge;
278 }
279
280 static void free_backref_edge(struct backref_cache *cache,
281 struct backref_edge *edge)
282 {
283 if (edge) {
284 cache->nr_edges--;
285 kfree(edge);
286 }
287 }
288
289 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
290 struct rb_node *node)
291 {
292 struct rb_node **p = &root->rb_node;
293 struct rb_node *parent = NULL;
294 struct tree_entry *entry;
295
296 while (*p) {
297 parent = *p;
298 entry = rb_entry(parent, struct tree_entry, rb_node);
299
300 if (bytenr < entry->bytenr)
301 p = &(*p)->rb_left;
302 else if (bytenr > entry->bytenr)
303 p = &(*p)->rb_right;
304 else
305 return parent;
306 }
307
308 rb_link_node(node, parent, p);
309 rb_insert_color(node, root);
310 return NULL;
311 }
312
313 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
314 {
315 struct rb_node *n = root->rb_node;
316 struct tree_entry *entry;
317
318 while (n) {
319 entry = rb_entry(n, struct tree_entry, rb_node);
320
321 if (bytenr < entry->bytenr)
322 n = n->rb_left;
323 else if (bytenr > entry->bytenr)
324 n = n->rb_right;
325 else
326 return n;
327 }
328 return NULL;
329 }
330
331 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
332 {
333
334 struct btrfs_fs_info *fs_info = NULL;
335 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
336 rb_node);
337 if (bnode->root)
338 fs_info = bnode->root->fs_info;
339 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
340 "found at offset %llu", bytenr);
341 }
342
343 /*
344 * walk up backref nodes until reach node presents tree root
345 */
346 static struct backref_node *walk_up_backref(struct backref_node *node,
347 struct backref_edge *edges[],
348 int *index)
349 {
350 struct backref_edge *edge;
351 int idx = *index;
352
353 while (!list_empty(&node->upper)) {
354 edge = list_entry(node->upper.next,
355 struct backref_edge, list[LOWER]);
356 edges[idx++] = edge;
357 node = edge->node[UPPER];
358 }
359 BUG_ON(node->detached);
360 *index = idx;
361 return node;
362 }
363
364 /*
365 * walk down backref nodes to find start of next reference path
366 */
367 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
368 int *index)
369 {
370 struct backref_edge *edge;
371 struct backref_node *lower;
372 int idx = *index;
373
374 while (idx > 0) {
375 edge = edges[idx - 1];
376 lower = edge->node[LOWER];
377 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
378 idx--;
379 continue;
380 }
381 edge = list_entry(edge->list[LOWER].next,
382 struct backref_edge, list[LOWER]);
383 edges[idx - 1] = edge;
384 *index = idx;
385 return edge->node[UPPER];
386 }
387 *index = 0;
388 return NULL;
389 }
390
391 static void unlock_node_buffer(struct backref_node *node)
392 {
393 if (node->locked) {
394 btrfs_tree_unlock(node->eb);
395 node->locked = 0;
396 }
397 }
398
399 static void drop_node_buffer(struct backref_node *node)
400 {
401 if (node->eb) {
402 unlock_node_buffer(node);
403 free_extent_buffer(node->eb);
404 node->eb = NULL;
405 }
406 }
407
408 static void drop_backref_node(struct backref_cache *tree,
409 struct backref_node *node)
410 {
411 BUG_ON(!list_empty(&node->upper));
412
413 drop_node_buffer(node);
414 list_del(&node->list);
415 list_del(&node->lower);
416 if (!RB_EMPTY_NODE(&node->rb_node))
417 rb_erase(&node->rb_node, &tree->rb_root);
418 free_backref_node(tree, node);
419 }
420
421 /*
422 * remove a backref node from the backref cache
423 */
424 static void remove_backref_node(struct backref_cache *cache,
425 struct backref_node *node)
426 {
427 struct backref_node *upper;
428 struct backref_edge *edge;
429
430 if (!node)
431 return;
432
433 BUG_ON(!node->lowest && !node->detached);
434 while (!list_empty(&node->upper)) {
435 edge = list_entry(node->upper.next, struct backref_edge,
436 list[LOWER]);
437 upper = edge->node[UPPER];
438 list_del(&edge->list[LOWER]);
439 list_del(&edge->list[UPPER]);
440 free_backref_edge(cache, edge);
441
442 if (RB_EMPTY_NODE(&upper->rb_node)) {
443 BUG_ON(!list_empty(&node->upper));
444 drop_backref_node(cache, node);
445 node = upper;
446 node->lowest = 1;
447 continue;
448 }
449 /*
450 * add the node to leaf node list if no other
451 * child block cached.
452 */
453 if (list_empty(&upper->lower)) {
454 list_add_tail(&upper->lower, &cache->leaves);
455 upper->lowest = 1;
456 }
457 }
458
459 drop_backref_node(cache, node);
460 }
461
462 static void update_backref_node(struct backref_cache *cache,
463 struct backref_node *node, u64 bytenr)
464 {
465 struct rb_node *rb_node;
466 rb_erase(&node->rb_node, &cache->rb_root);
467 node->bytenr = bytenr;
468 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
469 if (rb_node)
470 backref_tree_panic(rb_node, -EEXIST, bytenr);
471 }
472
473 /*
474 * update backref cache after a transaction commit
475 */
476 static int update_backref_cache(struct btrfs_trans_handle *trans,
477 struct backref_cache *cache)
478 {
479 struct backref_node *node;
480 int level = 0;
481
482 if (cache->last_trans == 0) {
483 cache->last_trans = trans->transid;
484 return 0;
485 }
486
487 if (cache->last_trans == trans->transid)
488 return 0;
489
490 /*
491 * detached nodes are used to avoid unnecessary backref
492 * lookup. transaction commit changes the extent tree.
493 * so the detached nodes are no longer useful.
494 */
495 while (!list_empty(&cache->detached)) {
496 node = list_entry(cache->detached.next,
497 struct backref_node, list);
498 remove_backref_node(cache, node);
499 }
500
501 while (!list_empty(&cache->changed)) {
502 node = list_entry(cache->changed.next,
503 struct backref_node, list);
504 list_del_init(&node->list);
505 BUG_ON(node->pending);
506 update_backref_node(cache, node, node->new_bytenr);
507 }
508
509 /*
510 * some nodes can be left in the pending list if there were
511 * errors during processing the pending nodes.
512 */
513 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
514 list_for_each_entry(node, &cache->pending[level], list) {
515 BUG_ON(!node->pending);
516 if (node->bytenr == node->new_bytenr)
517 continue;
518 update_backref_node(cache, node, node->new_bytenr);
519 }
520 }
521
522 cache->last_trans = 0;
523 return 1;
524 }
525
526
527 static int should_ignore_root(struct btrfs_root *root)
528 {
529 struct btrfs_root *reloc_root;
530
531 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
532 return 0;
533
534 reloc_root = root->reloc_root;
535 if (!reloc_root)
536 return 0;
537
538 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
539 root->fs_info->running_transaction->transid - 1)
540 return 0;
541 /*
542 * if there is reloc tree and it was created in previous
543 * transaction backref lookup can find the reloc tree,
544 * so backref node for the fs tree root is useless for
545 * relocation.
546 */
547 return 1;
548 }
549 /*
550 * find reloc tree by address of tree root
551 */
552 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
553 u64 bytenr)
554 {
555 struct rb_node *rb_node;
556 struct mapping_node *node;
557 struct btrfs_root *root = NULL;
558
559 spin_lock(&rc->reloc_root_tree.lock);
560 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
561 if (rb_node) {
562 node = rb_entry(rb_node, struct mapping_node, rb_node);
563 root = (struct btrfs_root *)node->data;
564 }
565 spin_unlock(&rc->reloc_root_tree.lock);
566 return root;
567 }
568
569 static int is_cowonly_root(u64 root_objectid)
570 {
571 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
572 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
573 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
574 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
575 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
576 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
577 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
578 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
579 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
580 return 1;
581 return 0;
582 }
583
584 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
585 u64 root_objectid)
586 {
587 struct btrfs_key key;
588
589 key.objectid = root_objectid;
590 key.type = BTRFS_ROOT_ITEM_KEY;
591 if (is_cowonly_root(root_objectid))
592 key.offset = 0;
593 else
594 key.offset = (u64)-1;
595
596 return btrfs_get_fs_root(fs_info, &key, false);
597 }
598
599 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
600 static noinline_for_stack
601 struct btrfs_root *find_tree_root(struct reloc_control *rc,
602 struct extent_buffer *leaf,
603 struct btrfs_extent_ref_v0 *ref0)
604 {
605 struct btrfs_root *root;
606 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
607 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
608
609 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
610
611 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
612 BUG_ON(IS_ERR(root));
613
614 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
615 generation != btrfs_root_generation(&root->root_item))
616 return NULL;
617
618 return root;
619 }
620 #endif
621
622 static noinline_for_stack
623 int find_inline_backref(struct extent_buffer *leaf, int slot,
624 unsigned long *ptr, unsigned long *end)
625 {
626 struct btrfs_key key;
627 struct btrfs_extent_item *ei;
628 struct btrfs_tree_block_info *bi;
629 u32 item_size;
630
631 btrfs_item_key_to_cpu(leaf, &key, slot);
632
633 item_size = btrfs_item_size_nr(leaf, slot);
634 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
635 if (item_size < sizeof(*ei)) {
636 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
637 return 1;
638 }
639 #endif
640 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
641 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
642 BTRFS_EXTENT_FLAG_TREE_BLOCK));
643
644 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
645 item_size <= sizeof(*ei) + sizeof(*bi)) {
646 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
647 return 1;
648 }
649 if (key.type == BTRFS_METADATA_ITEM_KEY &&
650 item_size <= sizeof(*ei)) {
651 WARN_ON(item_size < sizeof(*ei));
652 return 1;
653 }
654
655 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
656 bi = (struct btrfs_tree_block_info *)(ei + 1);
657 *ptr = (unsigned long)(bi + 1);
658 } else {
659 *ptr = (unsigned long)(ei + 1);
660 }
661 *end = (unsigned long)ei + item_size;
662 return 0;
663 }
664
665 /*
666 * build backref tree for a given tree block. root of the backref tree
667 * corresponds the tree block, leaves of the backref tree correspond
668 * roots of b-trees that reference the tree block.
669 *
670 * the basic idea of this function is check backrefs of a given block
671 * to find upper level blocks that reference the block, and then check
672 * backrefs of these upper level blocks recursively. the recursion stop
673 * when tree root is reached or backrefs for the block is cached.
674 *
675 * NOTE: if we find backrefs for a block are cached, we know backrefs
676 * for all upper level blocks that directly/indirectly reference the
677 * block are also cached.
678 */
679 static noinline_for_stack
680 struct backref_node *build_backref_tree(struct reloc_control *rc,
681 struct btrfs_key *node_key,
682 int level, u64 bytenr)
683 {
684 struct backref_cache *cache = &rc->backref_cache;
685 struct btrfs_path *path1;
686 struct btrfs_path *path2;
687 struct extent_buffer *eb;
688 struct btrfs_root *root;
689 struct backref_node *cur;
690 struct backref_node *upper;
691 struct backref_node *lower;
692 struct backref_node *node = NULL;
693 struct backref_node *exist = NULL;
694 struct backref_edge *edge;
695 struct rb_node *rb_node;
696 struct btrfs_key key;
697 unsigned long end;
698 unsigned long ptr;
699 LIST_HEAD(list);
700 LIST_HEAD(useless);
701 int cowonly;
702 int ret;
703 int err = 0;
704 bool need_check = true;
705
706 path1 = btrfs_alloc_path();
707 path2 = btrfs_alloc_path();
708 if (!path1 || !path2) {
709 err = -ENOMEM;
710 goto out;
711 }
712 path1->reada = READA_FORWARD;
713 path2->reada = READA_FORWARD;
714
715 node = alloc_backref_node(cache);
716 if (!node) {
717 err = -ENOMEM;
718 goto out;
719 }
720
721 node->bytenr = bytenr;
722 node->level = level;
723 node->lowest = 1;
724 cur = node;
725 again:
726 end = 0;
727 ptr = 0;
728 key.objectid = cur->bytenr;
729 key.type = BTRFS_METADATA_ITEM_KEY;
730 key.offset = (u64)-1;
731
732 path1->search_commit_root = 1;
733 path1->skip_locking = 1;
734 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
735 0, 0);
736 if (ret < 0) {
737 err = ret;
738 goto out;
739 }
740 ASSERT(ret);
741 ASSERT(path1->slots[0]);
742
743 path1->slots[0]--;
744
745 WARN_ON(cur->checked);
746 if (!list_empty(&cur->upper)) {
747 /*
748 * the backref was added previously when processing
749 * backref of type BTRFS_TREE_BLOCK_REF_KEY
750 */
751 ASSERT(list_is_singular(&cur->upper));
752 edge = list_entry(cur->upper.next, struct backref_edge,
753 list[LOWER]);
754 ASSERT(list_empty(&edge->list[UPPER]));
755 exist = edge->node[UPPER];
756 /*
757 * add the upper level block to pending list if we need
758 * check its backrefs
759 */
760 if (!exist->checked)
761 list_add_tail(&edge->list[UPPER], &list);
762 } else {
763 exist = NULL;
764 }
765
766 while (1) {
767 cond_resched();
768 eb = path1->nodes[0];
769
770 if (ptr >= end) {
771 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
772 ret = btrfs_next_leaf(rc->extent_root, path1);
773 if (ret < 0) {
774 err = ret;
775 goto out;
776 }
777 if (ret > 0)
778 break;
779 eb = path1->nodes[0];
780 }
781
782 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
783 if (key.objectid != cur->bytenr) {
784 WARN_ON(exist);
785 break;
786 }
787
788 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
789 key.type == BTRFS_METADATA_ITEM_KEY) {
790 ret = find_inline_backref(eb, path1->slots[0],
791 &ptr, &end);
792 if (ret)
793 goto next;
794 }
795 }
796
797 if (ptr < end) {
798 /* update key for inline back ref */
799 struct btrfs_extent_inline_ref *iref;
800 iref = (struct btrfs_extent_inline_ref *)ptr;
801 key.type = btrfs_extent_inline_ref_type(eb, iref);
802 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
803 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
804 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
805 }
806
807 if (exist &&
808 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
809 exist->owner == key.offset) ||
810 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
811 exist->bytenr == key.offset))) {
812 exist = NULL;
813 goto next;
814 }
815
816 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
817 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
818 key.type == BTRFS_EXTENT_REF_V0_KEY) {
819 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
820 struct btrfs_extent_ref_v0 *ref0;
821 ref0 = btrfs_item_ptr(eb, path1->slots[0],
822 struct btrfs_extent_ref_v0);
823 if (key.objectid == key.offset) {
824 root = find_tree_root(rc, eb, ref0);
825 if (root && !should_ignore_root(root))
826 cur->root = root;
827 else
828 list_add(&cur->list, &useless);
829 break;
830 }
831 if (is_cowonly_root(btrfs_ref_root_v0(eb,
832 ref0)))
833 cur->cowonly = 1;
834 }
835 #else
836 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
837 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
838 #endif
839 if (key.objectid == key.offset) {
840 /*
841 * only root blocks of reloc trees use
842 * backref of this type.
843 */
844 root = find_reloc_root(rc, cur->bytenr);
845 ASSERT(root);
846 cur->root = root;
847 break;
848 }
849
850 edge = alloc_backref_edge(cache);
851 if (!edge) {
852 err = -ENOMEM;
853 goto out;
854 }
855 rb_node = tree_search(&cache->rb_root, key.offset);
856 if (!rb_node) {
857 upper = alloc_backref_node(cache);
858 if (!upper) {
859 free_backref_edge(cache, edge);
860 err = -ENOMEM;
861 goto out;
862 }
863 upper->bytenr = key.offset;
864 upper->level = cur->level + 1;
865 /*
866 * backrefs for the upper level block isn't
867 * cached, add the block to pending list
868 */
869 list_add_tail(&edge->list[UPPER], &list);
870 } else {
871 upper = rb_entry(rb_node, struct backref_node,
872 rb_node);
873 ASSERT(upper->checked);
874 INIT_LIST_HEAD(&edge->list[UPPER]);
875 }
876 list_add_tail(&edge->list[LOWER], &cur->upper);
877 edge->node[LOWER] = cur;
878 edge->node[UPPER] = upper;
879
880 goto next;
881 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
882 goto next;
883 }
884
885 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
886 root = read_fs_root(rc->extent_root->fs_info, key.offset);
887 if (IS_ERR(root)) {
888 err = PTR_ERR(root);
889 goto out;
890 }
891
892 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
893 cur->cowonly = 1;
894
895 if (btrfs_root_level(&root->root_item) == cur->level) {
896 /* tree root */
897 ASSERT(btrfs_root_bytenr(&root->root_item) ==
898 cur->bytenr);
899 if (should_ignore_root(root))
900 list_add(&cur->list, &useless);
901 else
902 cur->root = root;
903 break;
904 }
905
906 level = cur->level + 1;
907
908 /*
909 * searching the tree to find upper level blocks
910 * reference the block.
911 */
912 path2->search_commit_root = 1;
913 path2->skip_locking = 1;
914 path2->lowest_level = level;
915 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
916 path2->lowest_level = 0;
917 if (ret < 0) {
918 err = ret;
919 goto out;
920 }
921 if (ret > 0 && path2->slots[level] > 0)
922 path2->slots[level]--;
923
924 eb = path2->nodes[level];
925 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
926 cur->bytenr);
927
928 lower = cur;
929 need_check = true;
930 for (; level < BTRFS_MAX_LEVEL; level++) {
931 if (!path2->nodes[level]) {
932 ASSERT(btrfs_root_bytenr(&root->root_item) ==
933 lower->bytenr);
934 if (should_ignore_root(root))
935 list_add(&lower->list, &useless);
936 else
937 lower->root = root;
938 break;
939 }
940
941 edge = alloc_backref_edge(cache);
942 if (!edge) {
943 err = -ENOMEM;
944 goto out;
945 }
946
947 eb = path2->nodes[level];
948 rb_node = tree_search(&cache->rb_root, eb->start);
949 if (!rb_node) {
950 upper = alloc_backref_node(cache);
951 if (!upper) {
952 free_backref_edge(cache, edge);
953 err = -ENOMEM;
954 goto out;
955 }
956 upper->bytenr = eb->start;
957 upper->owner = btrfs_header_owner(eb);
958 upper->level = lower->level + 1;
959 if (!test_bit(BTRFS_ROOT_REF_COWS,
960 &root->state))
961 upper->cowonly = 1;
962
963 /*
964 * if we know the block isn't shared
965 * we can void checking its backrefs.
966 */
967 if (btrfs_block_can_be_shared(root, eb))
968 upper->checked = 0;
969 else
970 upper->checked = 1;
971
972 /*
973 * add the block to pending list if we
974 * need check its backrefs, we only do this once
975 * while walking up a tree as we will catch
976 * anything else later on.
977 */
978 if (!upper->checked && need_check) {
979 need_check = false;
980 list_add_tail(&edge->list[UPPER],
981 &list);
982 } else {
983 if (upper->checked)
984 need_check = true;
985 INIT_LIST_HEAD(&edge->list[UPPER]);
986 }
987 } else {
988 upper = rb_entry(rb_node, struct backref_node,
989 rb_node);
990 ASSERT(upper->checked);
991 INIT_LIST_HEAD(&edge->list[UPPER]);
992 if (!upper->owner)
993 upper->owner = btrfs_header_owner(eb);
994 }
995 list_add_tail(&edge->list[LOWER], &lower->upper);
996 edge->node[LOWER] = lower;
997 edge->node[UPPER] = upper;
998
999 if (rb_node)
1000 break;
1001 lower = upper;
1002 upper = NULL;
1003 }
1004 btrfs_release_path(path2);
1005 next:
1006 if (ptr < end) {
1007 ptr += btrfs_extent_inline_ref_size(key.type);
1008 if (ptr >= end) {
1009 WARN_ON(ptr > end);
1010 ptr = 0;
1011 end = 0;
1012 }
1013 }
1014 if (ptr >= end)
1015 path1->slots[0]++;
1016 }
1017 btrfs_release_path(path1);
1018
1019 cur->checked = 1;
1020 WARN_ON(exist);
1021
1022 /* the pending list isn't empty, take the first block to process */
1023 if (!list_empty(&list)) {
1024 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1025 list_del_init(&edge->list[UPPER]);
1026 cur = edge->node[UPPER];
1027 goto again;
1028 }
1029
1030 /*
1031 * everything goes well, connect backref nodes and insert backref nodes
1032 * into the cache.
1033 */
1034 ASSERT(node->checked);
1035 cowonly = node->cowonly;
1036 if (!cowonly) {
1037 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1038 &node->rb_node);
1039 if (rb_node)
1040 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1041 list_add_tail(&node->lower, &cache->leaves);
1042 }
1043
1044 list_for_each_entry(edge, &node->upper, list[LOWER])
1045 list_add_tail(&edge->list[UPPER], &list);
1046
1047 while (!list_empty(&list)) {
1048 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1049 list_del_init(&edge->list[UPPER]);
1050 upper = edge->node[UPPER];
1051 if (upper->detached) {
1052 list_del(&edge->list[LOWER]);
1053 lower = edge->node[LOWER];
1054 free_backref_edge(cache, edge);
1055 if (list_empty(&lower->upper))
1056 list_add(&lower->list, &useless);
1057 continue;
1058 }
1059
1060 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1061 if (upper->lowest) {
1062 list_del_init(&upper->lower);
1063 upper->lowest = 0;
1064 }
1065
1066 list_add_tail(&edge->list[UPPER], &upper->lower);
1067 continue;
1068 }
1069
1070 if (!upper->checked) {
1071 /*
1072 * Still want to blow up for developers since this is a
1073 * logic bug.
1074 */
1075 ASSERT(0);
1076 err = -EINVAL;
1077 goto out;
1078 }
1079 if (cowonly != upper->cowonly) {
1080 ASSERT(0);
1081 err = -EINVAL;
1082 goto out;
1083 }
1084
1085 if (!cowonly) {
1086 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1087 &upper->rb_node);
1088 if (rb_node)
1089 backref_tree_panic(rb_node, -EEXIST,
1090 upper->bytenr);
1091 }
1092
1093 list_add_tail(&edge->list[UPPER], &upper->lower);
1094
1095 list_for_each_entry(edge, &upper->upper, list[LOWER])
1096 list_add_tail(&edge->list[UPPER], &list);
1097 }
1098 /*
1099 * process useless backref nodes. backref nodes for tree leaves
1100 * are deleted from the cache. backref nodes for upper level
1101 * tree blocks are left in the cache to avoid unnecessary backref
1102 * lookup.
1103 */
1104 while (!list_empty(&useless)) {
1105 upper = list_entry(useless.next, struct backref_node, list);
1106 list_del_init(&upper->list);
1107 ASSERT(list_empty(&upper->upper));
1108 if (upper == node)
1109 node = NULL;
1110 if (upper->lowest) {
1111 list_del_init(&upper->lower);
1112 upper->lowest = 0;
1113 }
1114 while (!list_empty(&upper->lower)) {
1115 edge = list_entry(upper->lower.next,
1116 struct backref_edge, list[UPPER]);
1117 list_del(&edge->list[UPPER]);
1118 list_del(&edge->list[LOWER]);
1119 lower = edge->node[LOWER];
1120 free_backref_edge(cache, edge);
1121
1122 if (list_empty(&lower->upper))
1123 list_add(&lower->list, &useless);
1124 }
1125 __mark_block_processed(rc, upper);
1126 if (upper->level > 0) {
1127 list_add(&upper->list, &cache->detached);
1128 upper->detached = 1;
1129 } else {
1130 rb_erase(&upper->rb_node, &cache->rb_root);
1131 free_backref_node(cache, upper);
1132 }
1133 }
1134 out:
1135 btrfs_free_path(path1);
1136 btrfs_free_path(path2);
1137 if (err) {
1138 while (!list_empty(&useless)) {
1139 lower = list_entry(useless.next,
1140 struct backref_node, list);
1141 list_del_init(&lower->list);
1142 }
1143 while (!list_empty(&list)) {
1144 edge = list_first_entry(&list, struct backref_edge,
1145 list[UPPER]);
1146 list_del(&edge->list[UPPER]);
1147 list_del(&edge->list[LOWER]);
1148 lower = edge->node[LOWER];
1149 upper = edge->node[UPPER];
1150 free_backref_edge(cache, edge);
1151
1152 /*
1153 * Lower is no longer linked to any upper backref nodes
1154 * and isn't in the cache, we can free it ourselves.
1155 */
1156 if (list_empty(&lower->upper) &&
1157 RB_EMPTY_NODE(&lower->rb_node))
1158 list_add(&lower->list, &useless);
1159
1160 if (!RB_EMPTY_NODE(&upper->rb_node))
1161 continue;
1162
1163 /* Add this guy's upper edges to the list to process */
1164 list_for_each_entry(edge, &upper->upper, list[LOWER])
1165 list_add_tail(&edge->list[UPPER], &list);
1166 if (list_empty(&upper->upper))
1167 list_add(&upper->list, &useless);
1168 }
1169
1170 while (!list_empty(&useless)) {
1171 lower = list_entry(useless.next,
1172 struct backref_node, list);
1173 list_del_init(&lower->list);
1174 if (lower == node)
1175 node = NULL;
1176 free_backref_node(cache, lower);
1177 }
1178
1179 free_backref_node(cache, node);
1180 return ERR_PTR(err);
1181 }
1182 ASSERT(!node || !node->detached);
1183 return node;
1184 }
1185
1186 /*
1187 * helper to add backref node for the newly created snapshot.
1188 * the backref node is created by cloning backref node that
1189 * corresponds to root of source tree
1190 */
1191 static int clone_backref_node(struct btrfs_trans_handle *trans,
1192 struct reloc_control *rc,
1193 struct btrfs_root *src,
1194 struct btrfs_root *dest)
1195 {
1196 struct btrfs_root *reloc_root = src->reloc_root;
1197 struct backref_cache *cache = &rc->backref_cache;
1198 struct backref_node *node = NULL;
1199 struct backref_node *new_node;
1200 struct backref_edge *edge;
1201 struct backref_edge *new_edge;
1202 struct rb_node *rb_node;
1203
1204 if (cache->last_trans > 0)
1205 update_backref_cache(trans, cache);
1206
1207 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1208 if (rb_node) {
1209 node = rb_entry(rb_node, struct backref_node, rb_node);
1210 if (node->detached)
1211 node = NULL;
1212 else
1213 BUG_ON(node->new_bytenr != reloc_root->node->start);
1214 }
1215
1216 if (!node) {
1217 rb_node = tree_search(&cache->rb_root,
1218 reloc_root->commit_root->start);
1219 if (rb_node) {
1220 node = rb_entry(rb_node, struct backref_node,
1221 rb_node);
1222 BUG_ON(node->detached);
1223 }
1224 }
1225
1226 if (!node)
1227 return 0;
1228
1229 new_node = alloc_backref_node(cache);
1230 if (!new_node)
1231 return -ENOMEM;
1232
1233 new_node->bytenr = dest->node->start;
1234 new_node->level = node->level;
1235 new_node->lowest = node->lowest;
1236 new_node->checked = 1;
1237 new_node->root = dest;
1238
1239 if (!node->lowest) {
1240 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1241 new_edge = alloc_backref_edge(cache);
1242 if (!new_edge)
1243 goto fail;
1244
1245 new_edge->node[UPPER] = new_node;
1246 new_edge->node[LOWER] = edge->node[LOWER];
1247 list_add_tail(&new_edge->list[UPPER],
1248 &new_node->lower);
1249 }
1250 } else {
1251 list_add_tail(&new_node->lower, &cache->leaves);
1252 }
1253
1254 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1255 &new_node->rb_node);
1256 if (rb_node)
1257 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1258
1259 if (!new_node->lowest) {
1260 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1261 list_add_tail(&new_edge->list[LOWER],
1262 &new_edge->node[LOWER]->upper);
1263 }
1264 }
1265 return 0;
1266 fail:
1267 while (!list_empty(&new_node->lower)) {
1268 new_edge = list_entry(new_node->lower.next,
1269 struct backref_edge, list[UPPER]);
1270 list_del(&new_edge->list[UPPER]);
1271 free_backref_edge(cache, new_edge);
1272 }
1273 free_backref_node(cache, new_node);
1274 return -ENOMEM;
1275 }
1276
1277 /*
1278 * helper to add 'address of tree root -> reloc tree' mapping
1279 */
1280 static int __must_check __add_reloc_root(struct btrfs_root *root)
1281 {
1282 struct rb_node *rb_node;
1283 struct mapping_node *node;
1284 struct reloc_control *rc = root->fs_info->reloc_ctl;
1285
1286 node = kmalloc(sizeof(*node), GFP_NOFS);
1287 if (!node)
1288 return -ENOMEM;
1289
1290 node->bytenr = root->node->start;
1291 node->data = root;
1292
1293 spin_lock(&rc->reloc_root_tree.lock);
1294 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1295 node->bytenr, &node->rb_node);
1296 spin_unlock(&rc->reloc_root_tree.lock);
1297 if (rb_node) {
1298 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1299 "for start=%llu while inserting into relocation "
1300 "tree", node->bytenr);
1301 kfree(node);
1302 return -EEXIST;
1303 }
1304
1305 list_add_tail(&root->root_list, &rc->reloc_roots);
1306 return 0;
1307 }
1308
1309 /*
1310 * helper to delete the 'address of tree root -> reloc tree'
1311 * mapping
1312 */
1313 static void __del_reloc_root(struct btrfs_root *root)
1314 {
1315 struct rb_node *rb_node;
1316 struct mapping_node *node = NULL;
1317 struct reloc_control *rc = root->fs_info->reloc_ctl;
1318
1319 spin_lock(&rc->reloc_root_tree.lock);
1320 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1321 root->node->start);
1322 if (rb_node) {
1323 node = rb_entry(rb_node, struct mapping_node, rb_node);
1324 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1325 }
1326 spin_unlock(&rc->reloc_root_tree.lock);
1327
1328 if (!node)
1329 return;
1330 BUG_ON((struct btrfs_root *)node->data != root);
1331
1332 spin_lock(&root->fs_info->trans_lock);
1333 list_del_init(&root->root_list);
1334 spin_unlock(&root->fs_info->trans_lock);
1335 kfree(node);
1336 }
1337
1338 /*
1339 * helper to update the 'address of tree root -> reloc tree'
1340 * mapping
1341 */
1342 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1343 {
1344 struct rb_node *rb_node;
1345 struct mapping_node *node = NULL;
1346 struct reloc_control *rc = root->fs_info->reloc_ctl;
1347
1348 spin_lock(&rc->reloc_root_tree.lock);
1349 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1350 root->node->start);
1351 if (rb_node) {
1352 node = rb_entry(rb_node, struct mapping_node, rb_node);
1353 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1354 }
1355 spin_unlock(&rc->reloc_root_tree.lock);
1356
1357 if (!node)
1358 return 0;
1359 BUG_ON((struct btrfs_root *)node->data != root);
1360
1361 spin_lock(&rc->reloc_root_tree.lock);
1362 node->bytenr = new_bytenr;
1363 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1364 node->bytenr, &node->rb_node);
1365 spin_unlock(&rc->reloc_root_tree.lock);
1366 if (rb_node)
1367 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1368 return 0;
1369 }
1370
1371 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1372 struct btrfs_root *root, u64 objectid)
1373 {
1374 struct btrfs_root *reloc_root;
1375 struct extent_buffer *eb;
1376 struct btrfs_root_item *root_item;
1377 struct btrfs_key root_key;
1378 u64 last_snap = 0;
1379 int ret;
1380
1381 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1382 BUG_ON(!root_item);
1383
1384 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1385 root_key.type = BTRFS_ROOT_ITEM_KEY;
1386 root_key.offset = objectid;
1387
1388 if (root->root_key.objectid == objectid) {
1389 /* called by btrfs_init_reloc_root */
1390 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1391 BTRFS_TREE_RELOC_OBJECTID);
1392 BUG_ON(ret);
1393
1394 last_snap = btrfs_root_last_snapshot(&root->root_item);
1395 btrfs_set_root_last_snapshot(&root->root_item,
1396 trans->transid - 1);
1397 } else {
1398 /*
1399 * called by btrfs_reloc_post_snapshot_hook.
1400 * the source tree is a reloc tree, all tree blocks
1401 * modified after it was created have RELOC flag
1402 * set in their headers. so it's OK to not update
1403 * the 'last_snapshot'.
1404 */
1405 ret = btrfs_copy_root(trans, root, root->node, &eb,
1406 BTRFS_TREE_RELOC_OBJECTID);
1407 BUG_ON(ret);
1408 }
1409
1410 memcpy(root_item, &root->root_item, sizeof(*root_item));
1411 btrfs_set_root_bytenr(root_item, eb->start);
1412 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1413 btrfs_set_root_generation(root_item, trans->transid);
1414
1415 if (root->root_key.objectid == objectid) {
1416 btrfs_set_root_refs(root_item, 0);
1417 memset(&root_item->drop_progress, 0,
1418 sizeof(struct btrfs_disk_key));
1419 root_item->drop_level = 0;
1420 /*
1421 * abuse rtransid, it is safe because it is impossible to
1422 * receive data into a relocation tree.
1423 */
1424 btrfs_set_root_rtransid(root_item, last_snap);
1425 btrfs_set_root_otransid(root_item, trans->transid);
1426 }
1427
1428 btrfs_tree_unlock(eb);
1429 free_extent_buffer(eb);
1430
1431 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1432 &root_key, root_item);
1433 BUG_ON(ret);
1434 kfree(root_item);
1435
1436 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1437 BUG_ON(IS_ERR(reloc_root));
1438 reloc_root->last_trans = trans->transid;
1439 return reloc_root;
1440 }
1441
1442 /*
1443 * create reloc tree for a given fs tree. reloc tree is just a
1444 * snapshot of the fs tree with special root objectid.
1445 */
1446 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1447 struct btrfs_root *root)
1448 {
1449 struct btrfs_root *reloc_root;
1450 struct reloc_control *rc = root->fs_info->reloc_ctl;
1451 struct btrfs_block_rsv *rsv;
1452 int clear_rsv = 0;
1453 int ret;
1454
1455 if (root->reloc_root) {
1456 reloc_root = root->reloc_root;
1457 reloc_root->last_trans = trans->transid;
1458 return 0;
1459 }
1460
1461 if (!rc || !rc->create_reloc_tree ||
1462 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1463 return 0;
1464
1465 if (!trans->reloc_reserved) {
1466 rsv = trans->block_rsv;
1467 trans->block_rsv = rc->block_rsv;
1468 clear_rsv = 1;
1469 }
1470 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1471 if (clear_rsv)
1472 trans->block_rsv = rsv;
1473
1474 ret = __add_reloc_root(reloc_root);
1475 BUG_ON(ret < 0);
1476 root->reloc_root = reloc_root;
1477 return 0;
1478 }
1479
1480 /*
1481 * update root item of reloc tree
1482 */
1483 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1484 struct btrfs_root *root)
1485 {
1486 struct btrfs_root *reloc_root;
1487 struct btrfs_root_item *root_item;
1488 int ret;
1489
1490 if (!root->reloc_root)
1491 goto out;
1492
1493 reloc_root = root->reloc_root;
1494 root_item = &reloc_root->root_item;
1495
1496 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1497 btrfs_root_refs(root_item) == 0) {
1498 root->reloc_root = NULL;
1499 __del_reloc_root(reloc_root);
1500 }
1501
1502 if (reloc_root->commit_root != reloc_root->node) {
1503 btrfs_set_root_node(root_item, reloc_root->node);
1504 free_extent_buffer(reloc_root->commit_root);
1505 reloc_root->commit_root = btrfs_root_node(reloc_root);
1506 }
1507
1508 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1509 &reloc_root->root_key, root_item);
1510 BUG_ON(ret);
1511
1512 out:
1513 return 0;
1514 }
1515
1516 /*
1517 * helper to find first cached inode with inode number >= objectid
1518 * in a subvolume
1519 */
1520 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1521 {
1522 struct rb_node *node;
1523 struct rb_node *prev;
1524 struct btrfs_inode *entry;
1525 struct inode *inode;
1526
1527 spin_lock(&root->inode_lock);
1528 again:
1529 node = root->inode_tree.rb_node;
1530 prev = NULL;
1531 while (node) {
1532 prev = node;
1533 entry = rb_entry(node, struct btrfs_inode, rb_node);
1534
1535 if (objectid < btrfs_ino(&entry->vfs_inode))
1536 node = node->rb_left;
1537 else if (objectid > btrfs_ino(&entry->vfs_inode))
1538 node = node->rb_right;
1539 else
1540 break;
1541 }
1542 if (!node) {
1543 while (prev) {
1544 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1545 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1546 node = prev;
1547 break;
1548 }
1549 prev = rb_next(prev);
1550 }
1551 }
1552 while (node) {
1553 entry = rb_entry(node, struct btrfs_inode, rb_node);
1554 inode = igrab(&entry->vfs_inode);
1555 if (inode) {
1556 spin_unlock(&root->inode_lock);
1557 return inode;
1558 }
1559
1560 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1561 if (cond_resched_lock(&root->inode_lock))
1562 goto again;
1563
1564 node = rb_next(node);
1565 }
1566 spin_unlock(&root->inode_lock);
1567 return NULL;
1568 }
1569
1570 static int in_block_group(u64 bytenr,
1571 struct btrfs_block_group_cache *block_group)
1572 {
1573 if (bytenr >= block_group->key.objectid &&
1574 bytenr < block_group->key.objectid + block_group->key.offset)
1575 return 1;
1576 return 0;
1577 }
1578
1579 /*
1580 * get new location of data
1581 */
1582 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1583 u64 bytenr, u64 num_bytes)
1584 {
1585 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1586 struct btrfs_path *path;
1587 struct btrfs_file_extent_item *fi;
1588 struct extent_buffer *leaf;
1589 int ret;
1590
1591 path = btrfs_alloc_path();
1592 if (!path)
1593 return -ENOMEM;
1594
1595 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1596 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1597 bytenr, 0);
1598 if (ret < 0)
1599 goto out;
1600 if (ret > 0) {
1601 ret = -ENOENT;
1602 goto out;
1603 }
1604
1605 leaf = path->nodes[0];
1606 fi = btrfs_item_ptr(leaf, path->slots[0],
1607 struct btrfs_file_extent_item);
1608
1609 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1610 btrfs_file_extent_compression(leaf, fi) ||
1611 btrfs_file_extent_encryption(leaf, fi) ||
1612 btrfs_file_extent_other_encoding(leaf, fi));
1613
1614 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1615 ret = -EINVAL;
1616 goto out;
1617 }
1618
1619 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1620 ret = 0;
1621 out:
1622 btrfs_free_path(path);
1623 return ret;
1624 }
1625
1626 /*
1627 * update file extent items in the tree leaf to point to
1628 * the new locations.
1629 */
1630 static noinline_for_stack
1631 int replace_file_extents(struct btrfs_trans_handle *trans,
1632 struct reloc_control *rc,
1633 struct btrfs_root *root,
1634 struct extent_buffer *leaf)
1635 {
1636 struct btrfs_key key;
1637 struct btrfs_file_extent_item *fi;
1638 struct inode *inode = NULL;
1639 u64 parent;
1640 u64 bytenr;
1641 u64 new_bytenr = 0;
1642 u64 num_bytes;
1643 u64 end;
1644 u32 nritems;
1645 u32 i;
1646 int ret = 0;
1647 int first = 1;
1648 int dirty = 0;
1649
1650 if (rc->stage != UPDATE_DATA_PTRS)
1651 return 0;
1652
1653 /* reloc trees always use full backref */
1654 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1655 parent = leaf->start;
1656 else
1657 parent = 0;
1658
1659 nritems = btrfs_header_nritems(leaf);
1660 for (i = 0; i < nritems; i++) {
1661 cond_resched();
1662 btrfs_item_key_to_cpu(leaf, &key, i);
1663 if (key.type != BTRFS_EXTENT_DATA_KEY)
1664 continue;
1665 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1666 if (btrfs_file_extent_type(leaf, fi) ==
1667 BTRFS_FILE_EXTENT_INLINE)
1668 continue;
1669 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1670 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1671 if (bytenr == 0)
1672 continue;
1673 if (!in_block_group(bytenr, rc->block_group))
1674 continue;
1675
1676 /*
1677 * if we are modifying block in fs tree, wait for readpage
1678 * to complete and drop the extent cache
1679 */
1680 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1681 if (first) {
1682 inode = find_next_inode(root, key.objectid);
1683 first = 0;
1684 } else if (inode && btrfs_ino(inode) < key.objectid) {
1685 btrfs_add_delayed_iput(inode);
1686 inode = find_next_inode(root, key.objectid);
1687 }
1688 if (inode && btrfs_ino(inode) == key.objectid) {
1689 end = key.offset +
1690 btrfs_file_extent_num_bytes(leaf, fi);
1691 WARN_ON(!IS_ALIGNED(key.offset,
1692 root->sectorsize));
1693 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1694 end--;
1695 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1696 key.offset, end);
1697 if (!ret)
1698 continue;
1699
1700 btrfs_drop_extent_cache(inode, key.offset, end,
1701 1);
1702 unlock_extent(&BTRFS_I(inode)->io_tree,
1703 key.offset, end);
1704 }
1705 }
1706
1707 ret = get_new_location(rc->data_inode, &new_bytenr,
1708 bytenr, num_bytes);
1709 if (ret) {
1710 /*
1711 * Don't have to abort since we've not changed anything
1712 * in the file extent yet.
1713 */
1714 break;
1715 }
1716
1717 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1718 dirty = 1;
1719
1720 key.offset -= btrfs_file_extent_offset(leaf, fi);
1721 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1722 num_bytes, parent,
1723 btrfs_header_owner(leaf),
1724 key.objectid, key.offset);
1725 if (ret) {
1726 btrfs_abort_transaction(trans, ret);
1727 break;
1728 }
1729
1730 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1731 parent, btrfs_header_owner(leaf),
1732 key.objectid, key.offset);
1733 if (ret) {
1734 btrfs_abort_transaction(trans, ret);
1735 break;
1736 }
1737 }
1738 if (dirty)
1739 btrfs_mark_buffer_dirty(leaf);
1740 if (inode)
1741 btrfs_add_delayed_iput(inode);
1742 return ret;
1743 }
1744
1745 static noinline_for_stack
1746 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1747 struct btrfs_path *path, int level)
1748 {
1749 struct btrfs_disk_key key1;
1750 struct btrfs_disk_key key2;
1751 btrfs_node_key(eb, &key1, slot);
1752 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1753 return memcmp(&key1, &key2, sizeof(key1));
1754 }
1755
1756 /*
1757 * try to replace tree blocks in fs tree with the new blocks
1758 * in reloc tree. tree blocks haven't been modified since the
1759 * reloc tree was create can be replaced.
1760 *
1761 * if a block was replaced, level of the block + 1 is returned.
1762 * if no block got replaced, 0 is returned. if there are other
1763 * errors, a negative error number is returned.
1764 */
1765 static noinline_for_stack
1766 int replace_path(struct btrfs_trans_handle *trans,
1767 struct btrfs_root *dest, struct btrfs_root *src,
1768 struct btrfs_path *path, struct btrfs_key *next_key,
1769 int lowest_level, int max_level)
1770 {
1771 struct extent_buffer *eb;
1772 struct extent_buffer *parent;
1773 struct btrfs_key key;
1774 u64 old_bytenr;
1775 u64 new_bytenr;
1776 u64 old_ptr_gen;
1777 u64 new_ptr_gen;
1778 u64 last_snapshot;
1779 u32 blocksize;
1780 int cow = 0;
1781 int level;
1782 int ret;
1783 int slot;
1784
1785 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1786 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1787
1788 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1789 again:
1790 slot = path->slots[lowest_level];
1791 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1792
1793 eb = btrfs_lock_root_node(dest);
1794 btrfs_set_lock_blocking(eb);
1795 level = btrfs_header_level(eb);
1796
1797 if (level < lowest_level) {
1798 btrfs_tree_unlock(eb);
1799 free_extent_buffer(eb);
1800 return 0;
1801 }
1802
1803 if (cow) {
1804 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1805 BUG_ON(ret);
1806 }
1807 btrfs_set_lock_blocking(eb);
1808
1809 if (next_key) {
1810 next_key->objectid = (u64)-1;
1811 next_key->type = (u8)-1;
1812 next_key->offset = (u64)-1;
1813 }
1814
1815 parent = eb;
1816 while (1) {
1817 level = btrfs_header_level(parent);
1818 BUG_ON(level < lowest_level);
1819
1820 ret = btrfs_bin_search(parent, &key, level, &slot);
1821 if (ret && slot > 0)
1822 slot--;
1823
1824 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1825 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1826
1827 old_bytenr = btrfs_node_blockptr(parent, slot);
1828 blocksize = dest->nodesize;
1829 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1830
1831 if (level <= max_level) {
1832 eb = path->nodes[level];
1833 new_bytenr = btrfs_node_blockptr(eb,
1834 path->slots[level]);
1835 new_ptr_gen = btrfs_node_ptr_generation(eb,
1836 path->slots[level]);
1837 } else {
1838 new_bytenr = 0;
1839 new_ptr_gen = 0;
1840 }
1841
1842 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1843 ret = level;
1844 break;
1845 }
1846
1847 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1848 memcmp_node_keys(parent, slot, path, level)) {
1849 if (level <= lowest_level) {
1850 ret = 0;
1851 break;
1852 }
1853
1854 eb = read_tree_block(dest, old_bytenr, old_ptr_gen);
1855 if (IS_ERR(eb)) {
1856 ret = PTR_ERR(eb);
1857 break;
1858 } else if (!extent_buffer_uptodate(eb)) {
1859 ret = -EIO;
1860 free_extent_buffer(eb);
1861 break;
1862 }
1863 btrfs_tree_lock(eb);
1864 if (cow) {
1865 ret = btrfs_cow_block(trans, dest, eb, parent,
1866 slot, &eb);
1867 BUG_ON(ret);
1868 }
1869 btrfs_set_lock_blocking(eb);
1870
1871 btrfs_tree_unlock(parent);
1872 free_extent_buffer(parent);
1873
1874 parent = eb;
1875 continue;
1876 }
1877
1878 if (!cow) {
1879 btrfs_tree_unlock(parent);
1880 free_extent_buffer(parent);
1881 cow = 1;
1882 goto again;
1883 }
1884
1885 btrfs_node_key_to_cpu(path->nodes[level], &key,
1886 path->slots[level]);
1887 btrfs_release_path(path);
1888
1889 path->lowest_level = level;
1890 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1891 path->lowest_level = 0;
1892 BUG_ON(ret);
1893
1894 /*
1895 * swap blocks in fs tree and reloc tree.
1896 */
1897 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1898 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1899 btrfs_mark_buffer_dirty(parent);
1900
1901 btrfs_set_node_blockptr(path->nodes[level],
1902 path->slots[level], old_bytenr);
1903 btrfs_set_node_ptr_generation(path->nodes[level],
1904 path->slots[level], old_ptr_gen);
1905 btrfs_mark_buffer_dirty(path->nodes[level]);
1906
1907 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1908 path->nodes[level]->start,
1909 src->root_key.objectid, level - 1, 0);
1910 BUG_ON(ret);
1911 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1912 0, dest->root_key.objectid, level - 1,
1913 0);
1914 BUG_ON(ret);
1915
1916 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1917 path->nodes[level]->start,
1918 src->root_key.objectid, level - 1, 0);
1919 BUG_ON(ret);
1920
1921 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1922 0, dest->root_key.objectid, level - 1,
1923 0);
1924 BUG_ON(ret);
1925
1926 btrfs_unlock_up_safe(path, 0);
1927
1928 ret = level;
1929 break;
1930 }
1931 btrfs_tree_unlock(parent);
1932 free_extent_buffer(parent);
1933 return ret;
1934 }
1935
1936 /*
1937 * helper to find next relocated block in reloc tree
1938 */
1939 static noinline_for_stack
1940 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1941 int *level)
1942 {
1943 struct extent_buffer *eb;
1944 int i;
1945 u64 last_snapshot;
1946 u32 nritems;
1947
1948 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1949
1950 for (i = 0; i < *level; i++) {
1951 free_extent_buffer(path->nodes[i]);
1952 path->nodes[i] = NULL;
1953 }
1954
1955 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1956 eb = path->nodes[i];
1957 nritems = btrfs_header_nritems(eb);
1958 while (path->slots[i] + 1 < nritems) {
1959 path->slots[i]++;
1960 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1961 last_snapshot)
1962 continue;
1963
1964 *level = i;
1965 return 0;
1966 }
1967 free_extent_buffer(path->nodes[i]);
1968 path->nodes[i] = NULL;
1969 }
1970 return 1;
1971 }
1972
1973 /*
1974 * walk down reloc tree to find relocated block of lowest level
1975 */
1976 static noinline_for_stack
1977 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1978 int *level)
1979 {
1980 struct extent_buffer *eb = NULL;
1981 int i;
1982 u64 bytenr;
1983 u64 ptr_gen = 0;
1984 u64 last_snapshot;
1985 u32 nritems;
1986
1987 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1988
1989 for (i = *level; i > 0; i--) {
1990 eb = path->nodes[i];
1991 nritems = btrfs_header_nritems(eb);
1992 while (path->slots[i] < nritems) {
1993 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1994 if (ptr_gen > last_snapshot)
1995 break;
1996 path->slots[i]++;
1997 }
1998 if (path->slots[i] >= nritems) {
1999 if (i == *level)
2000 break;
2001 *level = i + 1;
2002 return 0;
2003 }
2004 if (i == 1) {
2005 *level = i;
2006 return 0;
2007 }
2008
2009 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2010 eb = read_tree_block(root, bytenr, ptr_gen);
2011 if (IS_ERR(eb)) {
2012 return PTR_ERR(eb);
2013 } else if (!extent_buffer_uptodate(eb)) {
2014 free_extent_buffer(eb);
2015 return -EIO;
2016 }
2017 BUG_ON(btrfs_header_level(eb) != i - 1);
2018 path->nodes[i - 1] = eb;
2019 path->slots[i - 1] = 0;
2020 }
2021 return 1;
2022 }
2023
2024 /*
2025 * invalidate extent cache for file extents whose key in range of
2026 * [min_key, max_key)
2027 */
2028 static int invalidate_extent_cache(struct btrfs_root *root,
2029 struct btrfs_key *min_key,
2030 struct btrfs_key *max_key)
2031 {
2032 struct inode *inode = NULL;
2033 u64 objectid;
2034 u64 start, end;
2035 u64 ino;
2036
2037 objectid = min_key->objectid;
2038 while (1) {
2039 cond_resched();
2040 iput(inode);
2041
2042 if (objectid > max_key->objectid)
2043 break;
2044
2045 inode = find_next_inode(root, objectid);
2046 if (!inode)
2047 break;
2048 ino = btrfs_ino(inode);
2049
2050 if (ino > max_key->objectid) {
2051 iput(inode);
2052 break;
2053 }
2054
2055 objectid = ino + 1;
2056 if (!S_ISREG(inode->i_mode))
2057 continue;
2058
2059 if (unlikely(min_key->objectid == ino)) {
2060 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2061 continue;
2062 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2063 start = 0;
2064 else {
2065 start = min_key->offset;
2066 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2067 }
2068 } else {
2069 start = 0;
2070 }
2071
2072 if (unlikely(max_key->objectid == ino)) {
2073 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2074 continue;
2075 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2076 end = (u64)-1;
2077 } else {
2078 if (max_key->offset == 0)
2079 continue;
2080 end = max_key->offset;
2081 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2082 end--;
2083 }
2084 } else {
2085 end = (u64)-1;
2086 }
2087
2088 /* the lock_extent waits for readpage to complete */
2089 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2090 btrfs_drop_extent_cache(inode, start, end, 1);
2091 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2092 }
2093 return 0;
2094 }
2095
2096 static int find_next_key(struct btrfs_path *path, int level,
2097 struct btrfs_key *key)
2098
2099 {
2100 while (level < BTRFS_MAX_LEVEL) {
2101 if (!path->nodes[level])
2102 break;
2103 if (path->slots[level] + 1 <
2104 btrfs_header_nritems(path->nodes[level])) {
2105 btrfs_node_key_to_cpu(path->nodes[level], key,
2106 path->slots[level] + 1);
2107 return 0;
2108 }
2109 level++;
2110 }
2111 return 1;
2112 }
2113
2114 /*
2115 * merge the relocated tree blocks in reloc tree with corresponding
2116 * fs tree.
2117 */
2118 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2119 struct btrfs_root *root)
2120 {
2121 LIST_HEAD(inode_list);
2122 struct btrfs_key key;
2123 struct btrfs_key next_key;
2124 struct btrfs_trans_handle *trans = NULL;
2125 struct btrfs_root *reloc_root;
2126 struct btrfs_root_item *root_item;
2127 struct btrfs_path *path;
2128 struct extent_buffer *leaf;
2129 int level;
2130 int max_level;
2131 int replaced = 0;
2132 int ret;
2133 int err = 0;
2134 u32 min_reserved;
2135
2136 path = btrfs_alloc_path();
2137 if (!path)
2138 return -ENOMEM;
2139 path->reada = READA_FORWARD;
2140
2141 reloc_root = root->reloc_root;
2142 root_item = &reloc_root->root_item;
2143
2144 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2145 level = btrfs_root_level(root_item);
2146 extent_buffer_get(reloc_root->node);
2147 path->nodes[level] = reloc_root->node;
2148 path->slots[level] = 0;
2149 } else {
2150 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2151
2152 level = root_item->drop_level;
2153 BUG_ON(level == 0);
2154 path->lowest_level = level;
2155 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2156 path->lowest_level = 0;
2157 if (ret < 0) {
2158 btrfs_free_path(path);
2159 return ret;
2160 }
2161
2162 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2163 path->slots[level]);
2164 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2165
2166 btrfs_unlock_up_safe(path, 0);
2167 }
2168
2169 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2170 memset(&next_key, 0, sizeof(next_key));
2171
2172 while (1) {
2173 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2174 BTRFS_RESERVE_FLUSH_ALL);
2175 if (ret) {
2176 err = ret;
2177 goto out;
2178 }
2179 trans = btrfs_start_transaction(root, 0);
2180 if (IS_ERR(trans)) {
2181 err = PTR_ERR(trans);
2182 trans = NULL;
2183 goto out;
2184 }
2185 trans->block_rsv = rc->block_rsv;
2186
2187 replaced = 0;
2188 max_level = level;
2189
2190 ret = walk_down_reloc_tree(reloc_root, path, &level);
2191 if (ret < 0) {
2192 err = ret;
2193 goto out;
2194 }
2195 if (ret > 0)
2196 break;
2197
2198 if (!find_next_key(path, level, &key) &&
2199 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2200 ret = 0;
2201 } else {
2202 ret = replace_path(trans, root, reloc_root, path,
2203 &next_key, level, max_level);
2204 }
2205 if (ret < 0) {
2206 err = ret;
2207 goto out;
2208 }
2209
2210 if (ret > 0) {
2211 level = ret;
2212 btrfs_node_key_to_cpu(path->nodes[level], &key,
2213 path->slots[level]);
2214 replaced = 1;
2215 }
2216
2217 ret = walk_up_reloc_tree(reloc_root, path, &level);
2218 if (ret > 0)
2219 break;
2220
2221 BUG_ON(level == 0);
2222 /*
2223 * save the merging progress in the drop_progress.
2224 * this is OK since root refs == 1 in this case.
2225 */
2226 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2227 path->slots[level]);
2228 root_item->drop_level = level;
2229
2230 btrfs_end_transaction_throttle(trans, root);
2231 trans = NULL;
2232
2233 btrfs_btree_balance_dirty(root);
2234
2235 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2236 invalidate_extent_cache(root, &key, &next_key);
2237 }
2238
2239 /*
2240 * handle the case only one block in the fs tree need to be
2241 * relocated and the block is tree root.
2242 */
2243 leaf = btrfs_lock_root_node(root);
2244 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2245 btrfs_tree_unlock(leaf);
2246 free_extent_buffer(leaf);
2247 if (ret < 0)
2248 err = ret;
2249 out:
2250 btrfs_free_path(path);
2251
2252 if (err == 0) {
2253 memset(&root_item->drop_progress, 0,
2254 sizeof(root_item->drop_progress));
2255 root_item->drop_level = 0;
2256 btrfs_set_root_refs(root_item, 0);
2257 btrfs_update_reloc_root(trans, root);
2258 }
2259
2260 if (trans)
2261 btrfs_end_transaction_throttle(trans, root);
2262
2263 btrfs_btree_balance_dirty(root);
2264
2265 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2266 invalidate_extent_cache(root, &key, &next_key);
2267
2268 return err;
2269 }
2270
2271 static noinline_for_stack
2272 int prepare_to_merge(struct reloc_control *rc, int err)
2273 {
2274 struct btrfs_root *root = rc->extent_root;
2275 struct btrfs_root *reloc_root;
2276 struct btrfs_trans_handle *trans;
2277 LIST_HEAD(reloc_roots);
2278 u64 num_bytes = 0;
2279 int ret;
2280
2281 mutex_lock(&root->fs_info->reloc_mutex);
2282 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2283 rc->merging_rsv_size += rc->nodes_relocated * 2;
2284 mutex_unlock(&root->fs_info->reloc_mutex);
2285
2286 again:
2287 if (!err) {
2288 num_bytes = rc->merging_rsv_size;
2289 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2290 BTRFS_RESERVE_FLUSH_ALL);
2291 if (ret)
2292 err = ret;
2293 }
2294
2295 trans = btrfs_join_transaction(rc->extent_root);
2296 if (IS_ERR(trans)) {
2297 if (!err)
2298 btrfs_block_rsv_release(rc->extent_root,
2299 rc->block_rsv, num_bytes);
2300 return PTR_ERR(trans);
2301 }
2302
2303 if (!err) {
2304 if (num_bytes != rc->merging_rsv_size) {
2305 btrfs_end_transaction(trans, rc->extent_root);
2306 btrfs_block_rsv_release(rc->extent_root,
2307 rc->block_rsv, num_bytes);
2308 goto again;
2309 }
2310 }
2311
2312 rc->merge_reloc_tree = 1;
2313
2314 while (!list_empty(&rc->reloc_roots)) {
2315 reloc_root = list_entry(rc->reloc_roots.next,
2316 struct btrfs_root, root_list);
2317 list_del_init(&reloc_root->root_list);
2318
2319 root = read_fs_root(reloc_root->fs_info,
2320 reloc_root->root_key.offset);
2321 BUG_ON(IS_ERR(root));
2322 BUG_ON(root->reloc_root != reloc_root);
2323
2324 /*
2325 * set reference count to 1, so btrfs_recover_relocation
2326 * knows it should resumes merging
2327 */
2328 if (!err)
2329 btrfs_set_root_refs(&reloc_root->root_item, 1);
2330 btrfs_update_reloc_root(trans, root);
2331
2332 list_add(&reloc_root->root_list, &reloc_roots);
2333 }
2334
2335 list_splice(&reloc_roots, &rc->reloc_roots);
2336
2337 if (!err)
2338 btrfs_commit_transaction(trans, rc->extent_root);
2339 else
2340 btrfs_end_transaction(trans, rc->extent_root);
2341 return err;
2342 }
2343
2344 static noinline_for_stack
2345 void free_reloc_roots(struct list_head *list)
2346 {
2347 struct btrfs_root *reloc_root;
2348
2349 while (!list_empty(list)) {
2350 reloc_root = list_entry(list->next, struct btrfs_root,
2351 root_list);
2352 __del_reloc_root(reloc_root);
2353 }
2354 }
2355
2356 static noinline_for_stack
2357 void merge_reloc_roots(struct reloc_control *rc)
2358 {
2359 struct btrfs_root *root;
2360 struct btrfs_root *reloc_root;
2361 u64 last_snap;
2362 u64 otransid;
2363 u64 objectid;
2364 LIST_HEAD(reloc_roots);
2365 int found = 0;
2366 int ret = 0;
2367 again:
2368 root = rc->extent_root;
2369
2370 /*
2371 * this serializes us with btrfs_record_root_in_transaction,
2372 * we have to make sure nobody is in the middle of
2373 * adding their roots to the list while we are
2374 * doing this splice
2375 */
2376 mutex_lock(&root->fs_info->reloc_mutex);
2377 list_splice_init(&rc->reloc_roots, &reloc_roots);
2378 mutex_unlock(&root->fs_info->reloc_mutex);
2379
2380 while (!list_empty(&reloc_roots)) {
2381 found = 1;
2382 reloc_root = list_entry(reloc_roots.next,
2383 struct btrfs_root, root_list);
2384
2385 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2386 root = read_fs_root(reloc_root->fs_info,
2387 reloc_root->root_key.offset);
2388 BUG_ON(IS_ERR(root));
2389 BUG_ON(root->reloc_root != reloc_root);
2390
2391 ret = merge_reloc_root(rc, root);
2392 if (ret) {
2393 if (list_empty(&reloc_root->root_list))
2394 list_add_tail(&reloc_root->root_list,
2395 &reloc_roots);
2396 goto out;
2397 }
2398 } else {
2399 list_del_init(&reloc_root->root_list);
2400 }
2401
2402 /*
2403 * we keep the old last snapshot transid in rtranid when we
2404 * created the relocation tree.
2405 */
2406 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2407 otransid = btrfs_root_otransid(&reloc_root->root_item);
2408 objectid = reloc_root->root_key.offset;
2409
2410 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2411 if (ret < 0) {
2412 if (list_empty(&reloc_root->root_list))
2413 list_add_tail(&reloc_root->root_list,
2414 &reloc_roots);
2415 goto out;
2416 }
2417 }
2418
2419 if (found) {
2420 found = 0;
2421 goto again;
2422 }
2423 out:
2424 if (ret) {
2425 btrfs_handle_fs_error(root->fs_info, ret, NULL);
2426 if (!list_empty(&reloc_roots))
2427 free_reloc_roots(&reloc_roots);
2428
2429 /* new reloc root may be added */
2430 mutex_lock(&root->fs_info->reloc_mutex);
2431 list_splice_init(&rc->reloc_roots, &reloc_roots);
2432 mutex_unlock(&root->fs_info->reloc_mutex);
2433 if (!list_empty(&reloc_roots))
2434 free_reloc_roots(&reloc_roots);
2435 }
2436
2437 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2438 }
2439
2440 static void free_block_list(struct rb_root *blocks)
2441 {
2442 struct tree_block *block;
2443 struct rb_node *rb_node;
2444 while ((rb_node = rb_first(blocks))) {
2445 block = rb_entry(rb_node, struct tree_block, rb_node);
2446 rb_erase(rb_node, blocks);
2447 kfree(block);
2448 }
2449 }
2450
2451 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2452 struct btrfs_root *reloc_root)
2453 {
2454 struct btrfs_root *root;
2455
2456 if (reloc_root->last_trans == trans->transid)
2457 return 0;
2458
2459 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2460 BUG_ON(IS_ERR(root));
2461 BUG_ON(root->reloc_root != reloc_root);
2462
2463 return btrfs_record_root_in_trans(trans, root);
2464 }
2465
2466 static noinline_for_stack
2467 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2468 struct reloc_control *rc,
2469 struct backref_node *node,
2470 struct backref_edge *edges[])
2471 {
2472 struct backref_node *next;
2473 struct btrfs_root *root;
2474 int index = 0;
2475
2476 next = node;
2477 while (1) {
2478 cond_resched();
2479 next = walk_up_backref(next, edges, &index);
2480 root = next->root;
2481 BUG_ON(!root);
2482 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2483
2484 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2485 record_reloc_root_in_trans(trans, root);
2486 break;
2487 }
2488
2489 btrfs_record_root_in_trans(trans, root);
2490 root = root->reloc_root;
2491
2492 if (next->new_bytenr != root->node->start) {
2493 BUG_ON(next->new_bytenr);
2494 BUG_ON(!list_empty(&next->list));
2495 next->new_bytenr = root->node->start;
2496 next->root = root;
2497 list_add_tail(&next->list,
2498 &rc->backref_cache.changed);
2499 __mark_block_processed(rc, next);
2500 break;
2501 }
2502
2503 WARN_ON(1);
2504 root = NULL;
2505 next = walk_down_backref(edges, &index);
2506 if (!next || next->level <= node->level)
2507 break;
2508 }
2509 if (!root)
2510 return NULL;
2511
2512 next = node;
2513 /* setup backref node path for btrfs_reloc_cow_block */
2514 while (1) {
2515 rc->backref_cache.path[next->level] = next;
2516 if (--index < 0)
2517 break;
2518 next = edges[index]->node[UPPER];
2519 }
2520 return root;
2521 }
2522
2523 /*
2524 * select a tree root for relocation. return NULL if the block
2525 * is reference counted. we should use do_relocation() in this
2526 * case. return a tree root pointer if the block isn't reference
2527 * counted. return -ENOENT if the block is root of reloc tree.
2528 */
2529 static noinline_for_stack
2530 struct btrfs_root *select_one_root(struct backref_node *node)
2531 {
2532 struct backref_node *next;
2533 struct btrfs_root *root;
2534 struct btrfs_root *fs_root = NULL;
2535 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2536 int index = 0;
2537
2538 next = node;
2539 while (1) {
2540 cond_resched();
2541 next = walk_up_backref(next, edges, &index);
2542 root = next->root;
2543 BUG_ON(!root);
2544
2545 /* no other choice for non-references counted tree */
2546 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2547 return root;
2548
2549 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2550 fs_root = root;
2551
2552 if (next != node)
2553 return NULL;
2554
2555 next = walk_down_backref(edges, &index);
2556 if (!next || next->level <= node->level)
2557 break;
2558 }
2559
2560 if (!fs_root)
2561 return ERR_PTR(-ENOENT);
2562 return fs_root;
2563 }
2564
2565 static noinline_for_stack
2566 u64 calcu_metadata_size(struct reloc_control *rc,
2567 struct backref_node *node, int reserve)
2568 {
2569 struct backref_node *next = node;
2570 struct backref_edge *edge;
2571 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2572 u64 num_bytes = 0;
2573 int index = 0;
2574
2575 BUG_ON(reserve && node->processed);
2576
2577 while (next) {
2578 cond_resched();
2579 while (1) {
2580 if (next->processed && (reserve || next != node))
2581 break;
2582
2583 num_bytes += rc->extent_root->nodesize;
2584
2585 if (list_empty(&next->upper))
2586 break;
2587
2588 edge = list_entry(next->upper.next,
2589 struct backref_edge, list[LOWER]);
2590 edges[index++] = edge;
2591 next = edge->node[UPPER];
2592 }
2593 next = walk_down_backref(edges, &index);
2594 }
2595 return num_bytes;
2596 }
2597
2598 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2599 struct reloc_control *rc,
2600 struct backref_node *node)
2601 {
2602 struct btrfs_root *root = rc->extent_root;
2603 u64 num_bytes;
2604 int ret;
2605 u64 tmp;
2606
2607 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2608
2609 trans->block_rsv = rc->block_rsv;
2610 rc->reserved_bytes += num_bytes;
2611
2612 /*
2613 * We are under a transaction here so we can only do limited flushing.
2614 * If we get an enospc just kick back -EAGAIN so we know to drop the
2615 * transaction and try to refill when we can flush all the things.
2616 */
2617 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2618 BTRFS_RESERVE_FLUSH_LIMIT);
2619 if (ret) {
2620 tmp = rc->extent_root->nodesize * RELOCATION_RESERVED_NODES;
2621 while (tmp <= rc->reserved_bytes)
2622 tmp <<= 1;
2623 /*
2624 * only one thread can access block_rsv at this point,
2625 * so we don't need hold lock to protect block_rsv.
2626 * we expand more reservation size here to allow enough
2627 * space for relocation and we will return eailer in
2628 * enospc case.
2629 */
2630 rc->block_rsv->size = tmp + rc->extent_root->nodesize *
2631 RELOCATION_RESERVED_NODES;
2632 return -EAGAIN;
2633 }
2634
2635 return 0;
2636 }
2637
2638 /*
2639 * relocate a block tree, and then update pointers in upper level
2640 * blocks that reference the block to point to the new location.
2641 *
2642 * if called by link_to_upper, the block has already been relocated.
2643 * in that case this function just updates pointers.
2644 */
2645 static int do_relocation(struct btrfs_trans_handle *trans,
2646 struct reloc_control *rc,
2647 struct backref_node *node,
2648 struct btrfs_key *key,
2649 struct btrfs_path *path, int lowest)
2650 {
2651 struct backref_node *upper;
2652 struct backref_edge *edge;
2653 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2654 struct btrfs_root *root;
2655 struct extent_buffer *eb;
2656 u32 blocksize;
2657 u64 bytenr;
2658 u64 generation;
2659 int slot;
2660 int ret;
2661 int err = 0;
2662
2663 BUG_ON(lowest && node->eb);
2664
2665 path->lowest_level = node->level + 1;
2666 rc->backref_cache.path[node->level] = node;
2667 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2668 cond_resched();
2669
2670 upper = edge->node[UPPER];
2671 root = select_reloc_root(trans, rc, upper, edges);
2672 BUG_ON(!root);
2673
2674 if (upper->eb && !upper->locked) {
2675 if (!lowest) {
2676 ret = btrfs_bin_search(upper->eb, key,
2677 upper->level, &slot);
2678 BUG_ON(ret);
2679 bytenr = btrfs_node_blockptr(upper->eb, slot);
2680 if (node->eb->start == bytenr)
2681 goto next;
2682 }
2683 drop_node_buffer(upper);
2684 }
2685
2686 if (!upper->eb) {
2687 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2688 if (ret < 0) {
2689 err = ret;
2690 break;
2691 }
2692 BUG_ON(ret > 0);
2693
2694 if (!upper->eb) {
2695 upper->eb = path->nodes[upper->level];
2696 path->nodes[upper->level] = NULL;
2697 } else {
2698 BUG_ON(upper->eb != path->nodes[upper->level]);
2699 }
2700
2701 upper->locked = 1;
2702 path->locks[upper->level] = 0;
2703
2704 slot = path->slots[upper->level];
2705 btrfs_release_path(path);
2706 } else {
2707 ret = btrfs_bin_search(upper->eb, key, upper->level,
2708 &slot);
2709 BUG_ON(ret);
2710 }
2711
2712 bytenr = btrfs_node_blockptr(upper->eb, slot);
2713 if (lowest) {
2714 BUG_ON(bytenr != node->bytenr);
2715 } else {
2716 if (node->eb->start == bytenr)
2717 goto next;
2718 }
2719
2720 blocksize = root->nodesize;
2721 generation = btrfs_node_ptr_generation(upper->eb, slot);
2722 eb = read_tree_block(root, bytenr, generation);
2723 if (IS_ERR(eb)) {
2724 err = PTR_ERR(eb);
2725 goto next;
2726 } else if (!extent_buffer_uptodate(eb)) {
2727 free_extent_buffer(eb);
2728 err = -EIO;
2729 goto next;
2730 }
2731 btrfs_tree_lock(eb);
2732 btrfs_set_lock_blocking(eb);
2733
2734 if (!node->eb) {
2735 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2736 slot, &eb);
2737 btrfs_tree_unlock(eb);
2738 free_extent_buffer(eb);
2739 if (ret < 0) {
2740 err = ret;
2741 goto next;
2742 }
2743 BUG_ON(node->eb != eb);
2744 } else {
2745 btrfs_set_node_blockptr(upper->eb, slot,
2746 node->eb->start);
2747 btrfs_set_node_ptr_generation(upper->eb, slot,
2748 trans->transid);
2749 btrfs_mark_buffer_dirty(upper->eb);
2750
2751 ret = btrfs_inc_extent_ref(trans, root,
2752 node->eb->start, blocksize,
2753 upper->eb->start,
2754 btrfs_header_owner(upper->eb),
2755 node->level, 0);
2756 BUG_ON(ret);
2757
2758 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2759 BUG_ON(ret);
2760 }
2761 next:
2762 if (!upper->pending)
2763 drop_node_buffer(upper);
2764 else
2765 unlock_node_buffer(upper);
2766 if (err)
2767 break;
2768 }
2769
2770 if (!err && node->pending) {
2771 drop_node_buffer(node);
2772 list_move_tail(&node->list, &rc->backref_cache.changed);
2773 node->pending = 0;
2774 }
2775
2776 path->lowest_level = 0;
2777 BUG_ON(err == -ENOSPC);
2778 return err;
2779 }
2780
2781 static int link_to_upper(struct btrfs_trans_handle *trans,
2782 struct reloc_control *rc,
2783 struct backref_node *node,
2784 struct btrfs_path *path)
2785 {
2786 struct btrfs_key key;
2787
2788 btrfs_node_key_to_cpu(node->eb, &key, 0);
2789 return do_relocation(trans, rc, node, &key, path, 0);
2790 }
2791
2792 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2793 struct reloc_control *rc,
2794 struct btrfs_path *path, int err)
2795 {
2796 LIST_HEAD(list);
2797 struct backref_cache *cache = &rc->backref_cache;
2798 struct backref_node *node;
2799 int level;
2800 int ret;
2801
2802 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2803 while (!list_empty(&cache->pending[level])) {
2804 node = list_entry(cache->pending[level].next,
2805 struct backref_node, list);
2806 list_move_tail(&node->list, &list);
2807 BUG_ON(!node->pending);
2808
2809 if (!err) {
2810 ret = link_to_upper(trans, rc, node, path);
2811 if (ret < 0)
2812 err = ret;
2813 }
2814 }
2815 list_splice_init(&list, &cache->pending[level]);
2816 }
2817 return err;
2818 }
2819
2820 static void mark_block_processed(struct reloc_control *rc,
2821 u64 bytenr, u32 blocksize)
2822 {
2823 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2824 EXTENT_DIRTY);
2825 }
2826
2827 static void __mark_block_processed(struct reloc_control *rc,
2828 struct backref_node *node)
2829 {
2830 u32 blocksize;
2831 if (node->level == 0 ||
2832 in_block_group(node->bytenr, rc->block_group)) {
2833 blocksize = rc->extent_root->nodesize;
2834 mark_block_processed(rc, node->bytenr, blocksize);
2835 }
2836 node->processed = 1;
2837 }
2838
2839 /*
2840 * mark a block and all blocks directly/indirectly reference the block
2841 * as processed.
2842 */
2843 static void update_processed_blocks(struct reloc_control *rc,
2844 struct backref_node *node)
2845 {
2846 struct backref_node *next = node;
2847 struct backref_edge *edge;
2848 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2849 int index = 0;
2850
2851 while (next) {
2852 cond_resched();
2853 while (1) {
2854 if (next->processed)
2855 break;
2856
2857 __mark_block_processed(rc, next);
2858
2859 if (list_empty(&next->upper))
2860 break;
2861
2862 edge = list_entry(next->upper.next,
2863 struct backref_edge, list[LOWER]);
2864 edges[index++] = edge;
2865 next = edge->node[UPPER];
2866 }
2867 next = walk_down_backref(edges, &index);
2868 }
2869 }
2870
2871 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2872 {
2873 u32 blocksize = rc->extent_root->nodesize;
2874
2875 if (test_range_bit(&rc->processed_blocks, bytenr,
2876 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2877 return 1;
2878 return 0;
2879 }
2880
2881 static int get_tree_block_key(struct reloc_control *rc,
2882 struct tree_block *block)
2883 {
2884 struct extent_buffer *eb;
2885
2886 BUG_ON(block->key_ready);
2887 eb = read_tree_block(rc->extent_root, block->bytenr,
2888 block->key.offset);
2889 if (IS_ERR(eb)) {
2890 return PTR_ERR(eb);
2891 } else if (!extent_buffer_uptodate(eb)) {
2892 free_extent_buffer(eb);
2893 return -EIO;
2894 }
2895 WARN_ON(btrfs_header_level(eb) != block->level);
2896 if (block->level == 0)
2897 btrfs_item_key_to_cpu(eb, &block->key, 0);
2898 else
2899 btrfs_node_key_to_cpu(eb, &block->key, 0);
2900 free_extent_buffer(eb);
2901 block->key_ready = 1;
2902 return 0;
2903 }
2904
2905 /*
2906 * helper function to relocate a tree block
2907 */
2908 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2909 struct reloc_control *rc,
2910 struct backref_node *node,
2911 struct btrfs_key *key,
2912 struct btrfs_path *path)
2913 {
2914 struct btrfs_root *root;
2915 int ret = 0;
2916
2917 if (!node)
2918 return 0;
2919
2920 BUG_ON(node->processed);
2921 root = select_one_root(node);
2922 if (root == ERR_PTR(-ENOENT)) {
2923 update_processed_blocks(rc, node);
2924 goto out;
2925 }
2926
2927 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2928 ret = reserve_metadata_space(trans, rc, node);
2929 if (ret)
2930 goto out;
2931 }
2932
2933 if (root) {
2934 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2935 BUG_ON(node->new_bytenr);
2936 BUG_ON(!list_empty(&node->list));
2937 btrfs_record_root_in_trans(trans, root);
2938 root = root->reloc_root;
2939 node->new_bytenr = root->node->start;
2940 node->root = root;
2941 list_add_tail(&node->list, &rc->backref_cache.changed);
2942 } else {
2943 path->lowest_level = node->level;
2944 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2945 btrfs_release_path(path);
2946 if (ret > 0)
2947 ret = 0;
2948 }
2949 if (!ret)
2950 update_processed_blocks(rc, node);
2951 } else {
2952 ret = do_relocation(trans, rc, node, key, path, 1);
2953 }
2954 out:
2955 if (ret || node->level == 0 || node->cowonly)
2956 remove_backref_node(&rc->backref_cache, node);
2957 return ret;
2958 }
2959
2960 /*
2961 * relocate a list of blocks
2962 */
2963 static noinline_for_stack
2964 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2965 struct reloc_control *rc, struct rb_root *blocks)
2966 {
2967 struct backref_node *node;
2968 struct btrfs_path *path;
2969 struct tree_block *block;
2970 struct rb_node *rb_node;
2971 int ret;
2972 int err = 0;
2973
2974 path = btrfs_alloc_path();
2975 if (!path) {
2976 err = -ENOMEM;
2977 goto out_free_blocks;
2978 }
2979
2980 rb_node = rb_first(blocks);
2981 while (rb_node) {
2982 block = rb_entry(rb_node, struct tree_block, rb_node);
2983 if (!block->key_ready)
2984 readahead_tree_block(rc->extent_root, block->bytenr);
2985 rb_node = rb_next(rb_node);
2986 }
2987
2988 rb_node = rb_first(blocks);
2989 while (rb_node) {
2990 block = rb_entry(rb_node, struct tree_block, rb_node);
2991 if (!block->key_ready) {
2992 err = get_tree_block_key(rc, block);
2993 if (err)
2994 goto out_free_path;
2995 }
2996 rb_node = rb_next(rb_node);
2997 }
2998
2999 rb_node = rb_first(blocks);
3000 while (rb_node) {
3001 block = rb_entry(rb_node, struct tree_block, rb_node);
3002
3003 node = build_backref_tree(rc, &block->key,
3004 block->level, block->bytenr);
3005 if (IS_ERR(node)) {
3006 err = PTR_ERR(node);
3007 goto out;
3008 }
3009
3010 ret = relocate_tree_block(trans, rc, node, &block->key,
3011 path);
3012 if (ret < 0) {
3013 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3014 err = ret;
3015 goto out;
3016 }
3017 rb_node = rb_next(rb_node);
3018 }
3019 out:
3020 err = finish_pending_nodes(trans, rc, path, err);
3021
3022 out_free_path:
3023 btrfs_free_path(path);
3024 out_free_blocks:
3025 free_block_list(blocks);
3026 return err;
3027 }
3028
3029 static noinline_for_stack
3030 int prealloc_file_extent_cluster(struct inode *inode,
3031 struct file_extent_cluster *cluster)
3032 {
3033 u64 alloc_hint = 0;
3034 u64 start;
3035 u64 end;
3036 u64 offset = BTRFS_I(inode)->index_cnt;
3037 u64 num_bytes;
3038 int nr = 0;
3039 int ret = 0;
3040
3041 BUG_ON(cluster->start != cluster->boundary[0]);
3042 inode_lock(inode);
3043
3044 ret = btrfs_check_data_free_space(inode, cluster->start,
3045 cluster->end + 1 - cluster->start);
3046 if (ret)
3047 goto out;
3048
3049 while (nr < cluster->nr) {
3050 start = cluster->boundary[nr] - offset;
3051 if (nr + 1 < cluster->nr)
3052 end = cluster->boundary[nr + 1] - 1 - offset;
3053 else
3054 end = cluster->end - offset;
3055
3056 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3057 num_bytes = end + 1 - start;
3058 ret = btrfs_prealloc_file_range(inode, 0, start,
3059 num_bytes, num_bytes,
3060 end + 1, &alloc_hint);
3061 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3062 if (ret)
3063 break;
3064 nr++;
3065 }
3066 btrfs_free_reserved_data_space(inode, cluster->start,
3067 cluster->end + 1 - cluster->start);
3068 out:
3069 inode_unlock(inode);
3070 return ret;
3071 }
3072
3073 static noinline_for_stack
3074 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3075 u64 block_start)
3076 {
3077 struct btrfs_root *root = BTRFS_I(inode)->root;
3078 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3079 struct extent_map *em;
3080 int ret = 0;
3081
3082 em = alloc_extent_map();
3083 if (!em)
3084 return -ENOMEM;
3085
3086 em->start = start;
3087 em->len = end + 1 - start;
3088 em->block_len = em->len;
3089 em->block_start = block_start;
3090 em->bdev = root->fs_info->fs_devices->latest_bdev;
3091 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3092
3093 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3094 while (1) {
3095 write_lock(&em_tree->lock);
3096 ret = add_extent_mapping(em_tree, em, 0);
3097 write_unlock(&em_tree->lock);
3098 if (ret != -EEXIST) {
3099 free_extent_map(em);
3100 break;
3101 }
3102 btrfs_drop_extent_cache(inode, start, end, 0);
3103 }
3104 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3105 return ret;
3106 }
3107
3108 static int relocate_file_extent_cluster(struct inode *inode,
3109 struct file_extent_cluster *cluster)
3110 {
3111 u64 page_start;
3112 u64 page_end;
3113 u64 offset = BTRFS_I(inode)->index_cnt;
3114 unsigned long index;
3115 unsigned long last_index;
3116 struct page *page;
3117 struct file_ra_state *ra;
3118 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3119 int nr = 0;
3120 int ret = 0;
3121
3122 if (!cluster->nr)
3123 return 0;
3124
3125 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3126 if (!ra)
3127 return -ENOMEM;
3128
3129 ret = prealloc_file_extent_cluster(inode, cluster);
3130 if (ret)
3131 goto out;
3132
3133 file_ra_state_init(ra, inode->i_mapping);
3134
3135 ret = setup_extent_mapping(inode, cluster->start - offset,
3136 cluster->end - offset, cluster->start);
3137 if (ret)
3138 goto out;
3139
3140 index = (cluster->start - offset) >> PAGE_SHIFT;
3141 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3142 while (index <= last_index) {
3143 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_SIZE);
3144 if (ret)
3145 goto out;
3146
3147 page = find_lock_page(inode->i_mapping, index);
3148 if (!page) {
3149 page_cache_sync_readahead(inode->i_mapping,
3150 ra, NULL, index,
3151 last_index + 1 - index);
3152 page = find_or_create_page(inode->i_mapping, index,
3153 mask);
3154 if (!page) {
3155 btrfs_delalloc_release_metadata(inode,
3156 PAGE_SIZE);
3157 ret = -ENOMEM;
3158 goto out;
3159 }
3160 }
3161
3162 if (PageReadahead(page)) {
3163 page_cache_async_readahead(inode->i_mapping,
3164 ra, NULL, page, index,
3165 last_index + 1 - index);
3166 }
3167
3168 if (!PageUptodate(page)) {
3169 btrfs_readpage(NULL, page);
3170 lock_page(page);
3171 if (!PageUptodate(page)) {
3172 unlock_page(page);
3173 put_page(page);
3174 btrfs_delalloc_release_metadata(inode,
3175 PAGE_SIZE);
3176 ret = -EIO;
3177 goto out;
3178 }
3179 }
3180
3181 page_start = page_offset(page);
3182 page_end = page_start + PAGE_SIZE - 1;
3183
3184 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3185
3186 set_page_extent_mapped(page);
3187
3188 if (nr < cluster->nr &&
3189 page_start + offset == cluster->boundary[nr]) {
3190 set_extent_bits(&BTRFS_I(inode)->io_tree,
3191 page_start, page_end,
3192 EXTENT_BOUNDARY);
3193 nr++;
3194 }
3195
3196 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3197 set_page_dirty(page);
3198
3199 unlock_extent(&BTRFS_I(inode)->io_tree,
3200 page_start, page_end);
3201 unlock_page(page);
3202 put_page(page);
3203
3204 index++;
3205 balance_dirty_pages_ratelimited(inode->i_mapping);
3206 btrfs_throttle(BTRFS_I(inode)->root);
3207 }
3208 WARN_ON(nr != cluster->nr);
3209 out:
3210 kfree(ra);
3211 return ret;
3212 }
3213
3214 static noinline_for_stack
3215 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3216 struct file_extent_cluster *cluster)
3217 {
3218 int ret;
3219
3220 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3221 ret = relocate_file_extent_cluster(inode, cluster);
3222 if (ret)
3223 return ret;
3224 cluster->nr = 0;
3225 }
3226
3227 if (!cluster->nr)
3228 cluster->start = extent_key->objectid;
3229 else
3230 BUG_ON(cluster->nr >= MAX_EXTENTS);
3231 cluster->end = extent_key->objectid + extent_key->offset - 1;
3232 cluster->boundary[cluster->nr] = extent_key->objectid;
3233 cluster->nr++;
3234
3235 if (cluster->nr >= MAX_EXTENTS) {
3236 ret = relocate_file_extent_cluster(inode, cluster);
3237 if (ret)
3238 return ret;
3239 cluster->nr = 0;
3240 }
3241 return 0;
3242 }
3243
3244 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3245 static int get_ref_objectid_v0(struct reloc_control *rc,
3246 struct btrfs_path *path,
3247 struct btrfs_key *extent_key,
3248 u64 *ref_objectid, int *path_change)
3249 {
3250 struct btrfs_key key;
3251 struct extent_buffer *leaf;
3252 struct btrfs_extent_ref_v0 *ref0;
3253 int ret;
3254 int slot;
3255
3256 leaf = path->nodes[0];
3257 slot = path->slots[0];
3258 while (1) {
3259 if (slot >= btrfs_header_nritems(leaf)) {
3260 ret = btrfs_next_leaf(rc->extent_root, path);
3261 if (ret < 0)
3262 return ret;
3263 BUG_ON(ret > 0);
3264 leaf = path->nodes[0];
3265 slot = path->slots[0];
3266 if (path_change)
3267 *path_change = 1;
3268 }
3269 btrfs_item_key_to_cpu(leaf, &key, slot);
3270 if (key.objectid != extent_key->objectid)
3271 return -ENOENT;
3272
3273 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3274 slot++;
3275 continue;
3276 }
3277 ref0 = btrfs_item_ptr(leaf, slot,
3278 struct btrfs_extent_ref_v0);
3279 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3280 break;
3281 }
3282 return 0;
3283 }
3284 #endif
3285
3286 /*
3287 * helper to add a tree block to the list.
3288 * the major work is getting the generation and level of the block
3289 */
3290 static int add_tree_block(struct reloc_control *rc,
3291 struct btrfs_key *extent_key,
3292 struct btrfs_path *path,
3293 struct rb_root *blocks)
3294 {
3295 struct extent_buffer *eb;
3296 struct btrfs_extent_item *ei;
3297 struct btrfs_tree_block_info *bi;
3298 struct tree_block *block;
3299 struct rb_node *rb_node;
3300 u32 item_size;
3301 int level = -1;
3302 u64 generation;
3303
3304 eb = path->nodes[0];
3305 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3306
3307 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3308 item_size >= sizeof(*ei) + sizeof(*bi)) {
3309 ei = btrfs_item_ptr(eb, path->slots[0],
3310 struct btrfs_extent_item);
3311 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3312 bi = (struct btrfs_tree_block_info *)(ei + 1);
3313 level = btrfs_tree_block_level(eb, bi);
3314 } else {
3315 level = (int)extent_key->offset;
3316 }
3317 generation = btrfs_extent_generation(eb, ei);
3318 } else {
3319 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3320 u64 ref_owner;
3321 int ret;
3322
3323 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3324 ret = get_ref_objectid_v0(rc, path, extent_key,
3325 &ref_owner, NULL);
3326 if (ret < 0)
3327 return ret;
3328 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3329 level = (int)ref_owner;
3330 /* FIXME: get real generation */
3331 generation = 0;
3332 #else
3333 BUG();
3334 #endif
3335 }
3336
3337 btrfs_release_path(path);
3338
3339 BUG_ON(level == -1);
3340
3341 block = kmalloc(sizeof(*block), GFP_NOFS);
3342 if (!block)
3343 return -ENOMEM;
3344
3345 block->bytenr = extent_key->objectid;
3346 block->key.objectid = rc->extent_root->nodesize;
3347 block->key.offset = generation;
3348 block->level = level;
3349 block->key_ready = 0;
3350
3351 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3352 if (rb_node)
3353 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3354
3355 return 0;
3356 }
3357
3358 /*
3359 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3360 */
3361 static int __add_tree_block(struct reloc_control *rc,
3362 u64 bytenr, u32 blocksize,
3363 struct rb_root *blocks)
3364 {
3365 struct btrfs_path *path;
3366 struct btrfs_key key;
3367 int ret;
3368 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3369 SKINNY_METADATA);
3370
3371 if (tree_block_processed(bytenr, rc))
3372 return 0;
3373
3374 if (tree_search(blocks, bytenr))
3375 return 0;
3376
3377 path = btrfs_alloc_path();
3378 if (!path)
3379 return -ENOMEM;
3380 again:
3381 key.objectid = bytenr;
3382 if (skinny) {
3383 key.type = BTRFS_METADATA_ITEM_KEY;
3384 key.offset = (u64)-1;
3385 } else {
3386 key.type = BTRFS_EXTENT_ITEM_KEY;
3387 key.offset = blocksize;
3388 }
3389
3390 path->search_commit_root = 1;
3391 path->skip_locking = 1;
3392 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3393 if (ret < 0)
3394 goto out;
3395
3396 if (ret > 0 && skinny) {
3397 if (path->slots[0]) {
3398 path->slots[0]--;
3399 btrfs_item_key_to_cpu(path->nodes[0], &key,
3400 path->slots[0]);
3401 if (key.objectid == bytenr &&
3402 (key.type == BTRFS_METADATA_ITEM_KEY ||
3403 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3404 key.offset == blocksize)))
3405 ret = 0;
3406 }
3407
3408 if (ret) {
3409 skinny = false;
3410 btrfs_release_path(path);
3411 goto again;
3412 }
3413 }
3414 BUG_ON(ret);
3415
3416 ret = add_tree_block(rc, &key, path, blocks);
3417 out:
3418 btrfs_free_path(path);
3419 return ret;
3420 }
3421
3422 /*
3423 * helper to check if the block use full backrefs for pointers in it
3424 */
3425 static int block_use_full_backref(struct reloc_control *rc,
3426 struct extent_buffer *eb)
3427 {
3428 u64 flags;
3429 int ret;
3430
3431 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3432 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3433 return 1;
3434
3435 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3436 eb->start, btrfs_header_level(eb), 1,
3437 NULL, &flags);
3438 BUG_ON(ret);
3439
3440 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3441 ret = 1;
3442 else
3443 ret = 0;
3444 return ret;
3445 }
3446
3447 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3448 struct btrfs_block_group_cache *block_group,
3449 struct inode *inode,
3450 u64 ino)
3451 {
3452 struct btrfs_key key;
3453 struct btrfs_root *root = fs_info->tree_root;
3454 struct btrfs_trans_handle *trans;
3455 int ret = 0;
3456
3457 if (inode)
3458 goto truncate;
3459
3460 key.objectid = ino;
3461 key.type = BTRFS_INODE_ITEM_KEY;
3462 key.offset = 0;
3463
3464 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3465 if (IS_ERR(inode) || is_bad_inode(inode)) {
3466 if (!IS_ERR(inode))
3467 iput(inode);
3468 return -ENOENT;
3469 }
3470
3471 truncate:
3472 ret = btrfs_check_trunc_cache_free_space(root,
3473 &fs_info->global_block_rsv);
3474 if (ret)
3475 goto out;
3476
3477 trans = btrfs_join_transaction(root);
3478 if (IS_ERR(trans)) {
3479 ret = PTR_ERR(trans);
3480 goto out;
3481 }
3482
3483 ret = btrfs_truncate_free_space_cache(root, trans, block_group, inode);
3484
3485 btrfs_end_transaction(trans, root);
3486 btrfs_btree_balance_dirty(root);
3487 out:
3488 iput(inode);
3489 return ret;
3490 }
3491
3492 /*
3493 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3494 * this function scans fs tree to find blocks reference the data extent
3495 */
3496 static int find_data_references(struct reloc_control *rc,
3497 struct btrfs_key *extent_key,
3498 struct extent_buffer *leaf,
3499 struct btrfs_extent_data_ref *ref,
3500 struct rb_root *blocks)
3501 {
3502 struct btrfs_path *path;
3503 struct tree_block *block;
3504 struct btrfs_root *root;
3505 struct btrfs_file_extent_item *fi;
3506 struct rb_node *rb_node;
3507 struct btrfs_key key;
3508 u64 ref_root;
3509 u64 ref_objectid;
3510 u64 ref_offset;
3511 u32 ref_count;
3512 u32 nritems;
3513 int err = 0;
3514 int added = 0;
3515 int counted;
3516 int ret;
3517
3518 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3519 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3520 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3521 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3522
3523 /*
3524 * This is an extent belonging to the free space cache, lets just delete
3525 * it and redo the search.
3526 */
3527 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3528 ret = delete_block_group_cache(rc->extent_root->fs_info,
3529 rc->block_group,
3530 NULL, ref_objectid);
3531 if (ret != -ENOENT)
3532 return ret;
3533 ret = 0;
3534 }
3535
3536 path = btrfs_alloc_path();
3537 if (!path)
3538 return -ENOMEM;
3539 path->reada = READA_FORWARD;
3540
3541 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3542 if (IS_ERR(root)) {
3543 err = PTR_ERR(root);
3544 goto out;
3545 }
3546
3547 key.objectid = ref_objectid;
3548 key.type = BTRFS_EXTENT_DATA_KEY;
3549 if (ref_offset > ((u64)-1 << 32))
3550 key.offset = 0;
3551 else
3552 key.offset = ref_offset;
3553
3554 path->search_commit_root = 1;
3555 path->skip_locking = 1;
3556 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3557 if (ret < 0) {
3558 err = ret;
3559 goto out;
3560 }
3561
3562 leaf = path->nodes[0];
3563 nritems = btrfs_header_nritems(leaf);
3564 /*
3565 * the references in tree blocks that use full backrefs
3566 * are not counted in
3567 */
3568 if (block_use_full_backref(rc, leaf))
3569 counted = 0;
3570 else
3571 counted = 1;
3572 rb_node = tree_search(blocks, leaf->start);
3573 if (rb_node) {
3574 if (counted)
3575 added = 1;
3576 else
3577 path->slots[0] = nritems;
3578 }
3579
3580 while (ref_count > 0) {
3581 while (path->slots[0] >= nritems) {
3582 ret = btrfs_next_leaf(root, path);
3583 if (ret < 0) {
3584 err = ret;
3585 goto out;
3586 }
3587 if (WARN_ON(ret > 0))
3588 goto out;
3589
3590 leaf = path->nodes[0];
3591 nritems = btrfs_header_nritems(leaf);
3592 added = 0;
3593
3594 if (block_use_full_backref(rc, leaf))
3595 counted = 0;
3596 else
3597 counted = 1;
3598 rb_node = tree_search(blocks, leaf->start);
3599 if (rb_node) {
3600 if (counted)
3601 added = 1;
3602 else
3603 path->slots[0] = nritems;
3604 }
3605 }
3606
3607 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3608 if (WARN_ON(key.objectid != ref_objectid ||
3609 key.type != BTRFS_EXTENT_DATA_KEY))
3610 break;
3611
3612 fi = btrfs_item_ptr(leaf, path->slots[0],
3613 struct btrfs_file_extent_item);
3614
3615 if (btrfs_file_extent_type(leaf, fi) ==
3616 BTRFS_FILE_EXTENT_INLINE)
3617 goto next;
3618
3619 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3620 extent_key->objectid)
3621 goto next;
3622
3623 key.offset -= btrfs_file_extent_offset(leaf, fi);
3624 if (key.offset != ref_offset)
3625 goto next;
3626
3627 if (counted)
3628 ref_count--;
3629 if (added)
3630 goto next;
3631
3632 if (!tree_block_processed(leaf->start, rc)) {
3633 block = kmalloc(sizeof(*block), GFP_NOFS);
3634 if (!block) {
3635 err = -ENOMEM;
3636 break;
3637 }
3638 block->bytenr = leaf->start;
3639 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3640 block->level = 0;
3641 block->key_ready = 1;
3642 rb_node = tree_insert(blocks, block->bytenr,
3643 &block->rb_node);
3644 if (rb_node)
3645 backref_tree_panic(rb_node, -EEXIST,
3646 block->bytenr);
3647 }
3648 if (counted)
3649 added = 1;
3650 else
3651 path->slots[0] = nritems;
3652 next:
3653 path->slots[0]++;
3654
3655 }
3656 out:
3657 btrfs_free_path(path);
3658 return err;
3659 }
3660
3661 /*
3662 * helper to find all tree blocks that reference a given data extent
3663 */
3664 static noinline_for_stack
3665 int add_data_references(struct reloc_control *rc,
3666 struct btrfs_key *extent_key,
3667 struct btrfs_path *path,
3668 struct rb_root *blocks)
3669 {
3670 struct btrfs_key key;
3671 struct extent_buffer *eb;
3672 struct btrfs_extent_data_ref *dref;
3673 struct btrfs_extent_inline_ref *iref;
3674 unsigned long ptr;
3675 unsigned long end;
3676 u32 blocksize = rc->extent_root->nodesize;
3677 int ret = 0;
3678 int err = 0;
3679
3680 eb = path->nodes[0];
3681 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3682 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3683 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3684 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3685 ptr = end;
3686 else
3687 #endif
3688 ptr += sizeof(struct btrfs_extent_item);
3689
3690 while (ptr < end) {
3691 iref = (struct btrfs_extent_inline_ref *)ptr;
3692 key.type = btrfs_extent_inline_ref_type(eb, iref);
3693 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3694 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3695 ret = __add_tree_block(rc, key.offset, blocksize,
3696 blocks);
3697 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3698 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3699 ret = find_data_references(rc, extent_key,
3700 eb, dref, blocks);
3701 } else {
3702 BUG();
3703 }
3704 if (ret) {
3705 err = ret;
3706 goto out;
3707 }
3708 ptr += btrfs_extent_inline_ref_size(key.type);
3709 }
3710 WARN_ON(ptr > end);
3711
3712 while (1) {
3713 cond_resched();
3714 eb = path->nodes[0];
3715 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3716 ret = btrfs_next_leaf(rc->extent_root, path);
3717 if (ret < 0) {
3718 err = ret;
3719 break;
3720 }
3721 if (ret > 0)
3722 break;
3723 eb = path->nodes[0];
3724 }
3725
3726 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3727 if (key.objectid != extent_key->objectid)
3728 break;
3729
3730 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3731 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3732 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3733 #else
3734 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3735 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3736 #endif
3737 ret = __add_tree_block(rc, key.offset, blocksize,
3738 blocks);
3739 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3740 dref = btrfs_item_ptr(eb, path->slots[0],
3741 struct btrfs_extent_data_ref);
3742 ret = find_data_references(rc, extent_key,
3743 eb, dref, blocks);
3744 } else {
3745 ret = 0;
3746 }
3747 if (ret) {
3748 err = ret;
3749 break;
3750 }
3751 path->slots[0]++;
3752 }
3753 out:
3754 btrfs_release_path(path);
3755 if (err)
3756 free_block_list(blocks);
3757 return err;
3758 }
3759
3760 /*
3761 * helper to find next unprocessed extent
3762 */
3763 static noinline_for_stack
3764 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3765 struct btrfs_key *extent_key)
3766 {
3767 struct btrfs_key key;
3768 struct extent_buffer *leaf;
3769 u64 start, end, last;
3770 int ret;
3771
3772 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3773 while (1) {
3774 cond_resched();
3775 if (rc->search_start >= last) {
3776 ret = 1;
3777 break;
3778 }
3779
3780 key.objectid = rc->search_start;
3781 key.type = BTRFS_EXTENT_ITEM_KEY;
3782 key.offset = 0;
3783
3784 path->search_commit_root = 1;
3785 path->skip_locking = 1;
3786 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3787 0, 0);
3788 if (ret < 0)
3789 break;
3790 next:
3791 leaf = path->nodes[0];
3792 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3793 ret = btrfs_next_leaf(rc->extent_root, path);
3794 if (ret != 0)
3795 break;
3796 leaf = path->nodes[0];
3797 }
3798
3799 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3800 if (key.objectid >= last) {
3801 ret = 1;
3802 break;
3803 }
3804
3805 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3806 key.type != BTRFS_METADATA_ITEM_KEY) {
3807 path->slots[0]++;
3808 goto next;
3809 }
3810
3811 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3812 key.objectid + key.offset <= rc->search_start) {
3813 path->slots[0]++;
3814 goto next;
3815 }
3816
3817 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3818 key.objectid + rc->extent_root->nodesize <=
3819 rc->search_start) {
3820 path->slots[0]++;
3821 goto next;
3822 }
3823
3824 ret = find_first_extent_bit(&rc->processed_blocks,
3825 key.objectid, &start, &end,
3826 EXTENT_DIRTY, NULL);
3827
3828 if (ret == 0 && start <= key.objectid) {
3829 btrfs_release_path(path);
3830 rc->search_start = end + 1;
3831 } else {
3832 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3833 rc->search_start = key.objectid + key.offset;
3834 else
3835 rc->search_start = key.objectid +
3836 rc->extent_root->nodesize;
3837 memcpy(extent_key, &key, sizeof(key));
3838 return 0;
3839 }
3840 }
3841 btrfs_release_path(path);
3842 return ret;
3843 }
3844
3845 static void set_reloc_control(struct reloc_control *rc)
3846 {
3847 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3848
3849 mutex_lock(&fs_info->reloc_mutex);
3850 fs_info->reloc_ctl = rc;
3851 mutex_unlock(&fs_info->reloc_mutex);
3852 }
3853
3854 static void unset_reloc_control(struct reloc_control *rc)
3855 {
3856 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3857
3858 mutex_lock(&fs_info->reloc_mutex);
3859 fs_info->reloc_ctl = NULL;
3860 mutex_unlock(&fs_info->reloc_mutex);
3861 }
3862
3863 static int check_extent_flags(u64 flags)
3864 {
3865 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3866 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3867 return 1;
3868 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3869 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3870 return 1;
3871 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3872 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3873 return 1;
3874 return 0;
3875 }
3876
3877 static noinline_for_stack
3878 int prepare_to_relocate(struct reloc_control *rc)
3879 {
3880 struct btrfs_trans_handle *trans;
3881 int ret;
3882
3883 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3884 BTRFS_BLOCK_RSV_TEMP);
3885 if (!rc->block_rsv)
3886 return -ENOMEM;
3887
3888 memset(&rc->cluster, 0, sizeof(rc->cluster));
3889 rc->search_start = rc->block_group->key.objectid;
3890 rc->extents_found = 0;
3891 rc->nodes_relocated = 0;
3892 rc->merging_rsv_size = 0;
3893 rc->reserved_bytes = 0;
3894 rc->block_rsv->size = rc->extent_root->nodesize *
3895 RELOCATION_RESERVED_NODES;
3896 ret = btrfs_block_rsv_refill(rc->extent_root,
3897 rc->block_rsv, rc->block_rsv->size,
3898 BTRFS_RESERVE_FLUSH_ALL);
3899 if (ret)
3900 return ret;
3901
3902 rc->create_reloc_tree = 1;
3903 set_reloc_control(rc);
3904
3905 trans = btrfs_join_transaction(rc->extent_root);
3906 if (IS_ERR(trans)) {
3907 unset_reloc_control(rc);
3908 /*
3909 * extent tree is not a ref_cow tree and has no reloc_root to
3910 * cleanup. And callers are responsible to free the above
3911 * block rsv.
3912 */
3913 return PTR_ERR(trans);
3914 }
3915 btrfs_commit_transaction(trans, rc->extent_root);
3916 return 0;
3917 }
3918
3919 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3920 {
3921 struct rb_root blocks = RB_ROOT;
3922 struct btrfs_key key;
3923 struct btrfs_trans_handle *trans = NULL;
3924 struct btrfs_path *path;
3925 struct btrfs_extent_item *ei;
3926 u64 flags;
3927 u32 item_size;
3928 int ret;
3929 int err = 0;
3930 int progress = 0;
3931
3932 path = btrfs_alloc_path();
3933 if (!path)
3934 return -ENOMEM;
3935 path->reada = READA_FORWARD;
3936
3937 ret = prepare_to_relocate(rc);
3938 if (ret) {
3939 err = ret;
3940 goto out_free;
3941 }
3942
3943 while (1) {
3944 rc->reserved_bytes = 0;
3945 ret = btrfs_block_rsv_refill(rc->extent_root,
3946 rc->block_rsv, rc->block_rsv->size,
3947 BTRFS_RESERVE_FLUSH_ALL);
3948 if (ret) {
3949 err = ret;
3950 break;
3951 }
3952 progress++;
3953 trans = btrfs_start_transaction(rc->extent_root, 0);
3954 if (IS_ERR(trans)) {
3955 err = PTR_ERR(trans);
3956 trans = NULL;
3957 break;
3958 }
3959 restart:
3960 if (update_backref_cache(trans, &rc->backref_cache)) {
3961 btrfs_end_transaction(trans, rc->extent_root);
3962 continue;
3963 }
3964
3965 ret = find_next_extent(rc, path, &key);
3966 if (ret < 0)
3967 err = ret;
3968 if (ret != 0)
3969 break;
3970
3971 rc->extents_found++;
3972
3973 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3974 struct btrfs_extent_item);
3975 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3976 if (item_size >= sizeof(*ei)) {
3977 flags = btrfs_extent_flags(path->nodes[0], ei);
3978 ret = check_extent_flags(flags);
3979 BUG_ON(ret);
3980
3981 } else {
3982 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3983 u64 ref_owner;
3984 int path_change = 0;
3985
3986 BUG_ON(item_size !=
3987 sizeof(struct btrfs_extent_item_v0));
3988 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3989 &path_change);
3990 if (ret < 0) {
3991 err = ret;
3992 break;
3993 }
3994 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3995 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3996 else
3997 flags = BTRFS_EXTENT_FLAG_DATA;
3998
3999 if (path_change) {
4000 btrfs_release_path(path);
4001
4002 path->search_commit_root = 1;
4003 path->skip_locking = 1;
4004 ret = btrfs_search_slot(NULL, rc->extent_root,
4005 &key, path, 0, 0);
4006 if (ret < 0) {
4007 err = ret;
4008 break;
4009 }
4010 BUG_ON(ret > 0);
4011 }
4012 #else
4013 BUG();
4014 #endif
4015 }
4016
4017 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4018 ret = add_tree_block(rc, &key, path, &blocks);
4019 } else if (rc->stage == UPDATE_DATA_PTRS &&
4020 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4021 ret = add_data_references(rc, &key, path, &blocks);
4022 } else {
4023 btrfs_release_path(path);
4024 ret = 0;
4025 }
4026 if (ret < 0) {
4027 err = ret;
4028 break;
4029 }
4030
4031 if (!RB_EMPTY_ROOT(&blocks)) {
4032 ret = relocate_tree_blocks(trans, rc, &blocks);
4033 if (ret < 0) {
4034 /*
4035 * if we fail to relocate tree blocks, force to update
4036 * backref cache when committing transaction.
4037 */
4038 rc->backref_cache.last_trans = trans->transid - 1;
4039
4040 if (ret != -EAGAIN) {
4041 err = ret;
4042 break;
4043 }
4044 rc->extents_found--;
4045 rc->search_start = key.objectid;
4046 }
4047 }
4048
4049 btrfs_end_transaction_throttle(trans, rc->extent_root);
4050 btrfs_btree_balance_dirty(rc->extent_root);
4051 trans = NULL;
4052
4053 if (rc->stage == MOVE_DATA_EXTENTS &&
4054 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4055 rc->found_file_extent = 1;
4056 ret = relocate_data_extent(rc->data_inode,
4057 &key, &rc->cluster);
4058 if (ret < 0) {
4059 err = ret;
4060 break;
4061 }
4062 }
4063 }
4064 if (trans && progress && err == -ENOSPC) {
4065 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4066 rc->block_group->flags);
4067 if (ret == 1) {
4068 err = 0;
4069 progress = 0;
4070 goto restart;
4071 }
4072 }
4073
4074 btrfs_release_path(path);
4075 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4076
4077 if (trans) {
4078 btrfs_end_transaction_throttle(trans, rc->extent_root);
4079 btrfs_btree_balance_dirty(rc->extent_root);
4080 }
4081
4082 if (!err) {
4083 ret = relocate_file_extent_cluster(rc->data_inode,
4084 &rc->cluster);
4085 if (ret < 0)
4086 err = ret;
4087 }
4088
4089 rc->create_reloc_tree = 0;
4090 set_reloc_control(rc);
4091
4092 backref_cache_cleanup(&rc->backref_cache);
4093 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4094
4095 err = prepare_to_merge(rc, err);
4096
4097 merge_reloc_roots(rc);
4098
4099 rc->merge_reloc_tree = 0;
4100 unset_reloc_control(rc);
4101 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4102
4103 /* get rid of pinned extents */
4104 trans = btrfs_join_transaction(rc->extent_root);
4105 if (IS_ERR(trans))
4106 err = PTR_ERR(trans);
4107 else
4108 btrfs_commit_transaction(trans, rc->extent_root);
4109 out_free:
4110 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4111 btrfs_free_path(path);
4112 return err;
4113 }
4114
4115 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4116 struct btrfs_root *root, u64 objectid)
4117 {
4118 struct btrfs_path *path;
4119 struct btrfs_inode_item *item;
4120 struct extent_buffer *leaf;
4121 int ret;
4122
4123 path = btrfs_alloc_path();
4124 if (!path)
4125 return -ENOMEM;
4126
4127 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4128 if (ret)
4129 goto out;
4130
4131 leaf = path->nodes[0];
4132 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4133 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4134 btrfs_set_inode_generation(leaf, item, 1);
4135 btrfs_set_inode_size(leaf, item, 0);
4136 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4137 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4138 BTRFS_INODE_PREALLOC);
4139 btrfs_mark_buffer_dirty(leaf);
4140 out:
4141 btrfs_free_path(path);
4142 return ret;
4143 }
4144
4145 /*
4146 * helper to create inode for data relocation.
4147 * the inode is in data relocation tree and its link count is 0
4148 */
4149 static noinline_for_stack
4150 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4151 struct btrfs_block_group_cache *group)
4152 {
4153 struct inode *inode = NULL;
4154 struct btrfs_trans_handle *trans;
4155 struct btrfs_root *root;
4156 struct btrfs_key key;
4157 u64 objectid;
4158 int err = 0;
4159
4160 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4161 if (IS_ERR(root))
4162 return ERR_CAST(root);
4163
4164 trans = btrfs_start_transaction(root, 6);
4165 if (IS_ERR(trans))
4166 return ERR_CAST(trans);
4167
4168 err = btrfs_find_free_objectid(root, &objectid);
4169 if (err)
4170 goto out;
4171
4172 err = __insert_orphan_inode(trans, root, objectid);
4173 BUG_ON(err);
4174
4175 key.objectid = objectid;
4176 key.type = BTRFS_INODE_ITEM_KEY;
4177 key.offset = 0;
4178 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4179 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4180 BTRFS_I(inode)->index_cnt = group->key.objectid;
4181
4182 err = btrfs_orphan_add(trans, inode);
4183 out:
4184 btrfs_end_transaction(trans, root);
4185 btrfs_btree_balance_dirty(root);
4186 if (err) {
4187 if (inode)
4188 iput(inode);
4189 inode = ERR_PTR(err);
4190 }
4191 return inode;
4192 }
4193
4194 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4195 {
4196 struct reloc_control *rc;
4197
4198 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4199 if (!rc)
4200 return NULL;
4201
4202 INIT_LIST_HEAD(&rc->reloc_roots);
4203 backref_cache_init(&rc->backref_cache);
4204 mapping_tree_init(&rc->reloc_root_tree);
4205 extent_io_tree_init(&rc->processed_blocks,
4206 fs_info->btree_inode->i_mapping);
4207 return rc;
4208 }
4209
4210 /*
4211 * function to relocate all extents in a block group.
4212 */
4213 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4214 {
4215 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4216 struct reloc_control *rc;
4217 struct inode *inode;
4218 struct btrfs_path *path;
4219 int ret;
4220 int rw = 0;
4221 int err = 0;
4222
4223 rc = alloc_reloc_control(fs_info);
4224 if (!rc)
4225 return -ENOMEM;
4226
4227 rc->extent_root = extent_root;
4228
4229 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4230 BUG_ON(!rc->block_group);
4231
4232 ret = btrfs_inc_block_group_ro(extent_root, rc->block_group);
4233 if (ret) {
4234 err = ret;
4235 goto out;
4236 }
4237 rw = 1;
4238
4239 path = btrfs_alloc_path();
4240 if (!path) {
4241 err = -ENOMEM;
4242 goto out;
4243 }
4244
4245 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4246 path);
4247 btrfs_free_path(path);
4248
4249 if (!IS_ERR(inode))
4250 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4251 else
4252 ret = PTR_ERR(inode);
4253
4254 if (ret && ret != -ENOENT) {
4255 err = ret;
4256 goto out;
4257 }
4258
4259 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4260 if (IS_ERR(rc->data_inode)) {
4261 err = PTR_ERR(rc->data_inode);
4262 rc->data_inode = NULL;
4263 goto out;
4264 }
4265
4266 btrfs_info(extent_root->fs_info, "relocating block group %llu flags %llu",
4267 rc->block_group->key.objectid, rc->block_group->flags);
4268
4269 btrfs_wait_block_group_reservations(rc->block_group);
4270 btrfs_wait_nocow_writers(rc->block_group);
4271 btrfs_wait_ordered_roots(fs_info, -1,
4272 rc->block_group->key.objectid,
4273 rc->block_group->key.offset);
4274
4275 while (1) {
4276 mutex_lock(&fs_info->cleaner_mutex);
4277 ret = relocate_block_group(rc);
4278 mutex_unlock(&fs_info->cleaner_mutex);
4279 if (ret < 0) {
4280 err = ret;
4281 goto out;
4282 }
4283
4284 if (rc->extents_found == 0)
4285 break;
4286
4287 btrfs_info(extent_root->fs_info, "found %llu extents",
4288 rc->extents_found);
4289
4290 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4291 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4292 (u64)-1);
4293 if (ret) {
4294 err = ret;
4295 goto out;
4296 }
4297 invalidate_mapping_pages(rc->data_inode->i_mapping,
4298 0, -1);
4299 rc->stage = UPDATE_DATA_PTRS;
4300 }
4301 }
4302
4303 WARN_ON(rc->block_group->pinned > 0);
4304 WARN_ON(rc->block_group->reserved > 0);
4305 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4306 out:
4307 if (err && rw)
4308 btrfs_dec_block_group_ro(extent_root, rc->block_group);
4309 iput(rc->data_inode);
4310 btrfs_put_block_group(rc->block_group);
4311 kfree(rc);
4312 return err;
4313 }
4314
4315 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4316 {
4317 struct btrfs_trans_handle *trans;
4318 int ret, err;
4319
4320 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4321 if (IS_ERR(trans))
4322 return PTR_ERR(trans);
4323
4324 memset(&root->root_item.drop_progress, 0,
4325 sizeof(root->root_item.drop_progress));
4326 root->root_item.drop_level = 0;
4327 btrfs_set_root_refs(&root->root_item, 0);
4328 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4329 &root->root_key, &root->root_item);
4330
4331 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4332 if (err)
4333 return err;
4334 return ret;
4335 }
4336
4337 /*
4338 * recover relocation interrupted by system crash.
4339 *
4340 * this function resumes merging reloc trees with corresponding fs trees.
4341 * this is important for keeping the sharing of tree blocks
4342 */
4343 int btrfs_recover_relocation(struct btrfs_root *root)
4344 {
4345 LIST_HEAD(reloc_roots);
4346 struct btrfs_key key;
4347 struct btrfs_root *fs_root;
4348 struct btrfs_root *reloc_root;
4349 struct btrfs_path *path;
4350 struct extent_buffer *leaf;
4351 struct reloc_control *rc = NULL;
4352 struct btrfs_trans_handle *trans;
4353 int ret;
4354 int err = 0;
4355
4356 path = btrfs_alloc_path();
4357 if (!path)
4358 return -ENOMEM;
4359 path->reada = READA_BACK;
4360
4361 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4362 key.type = BTRFS_ROOT_ITEM_KEY;
4363 key.offset = (u64)-1;
4364
4365 while (1) {
4366 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4367 path, 0, 0);
4368 if (ret < 0) {
4369 err = ret;
4370 goto out;
4371 }
4372 if (ret > 0) {
4373 if (path->slots[0] == 0)
4374 break;
4375 path->slots[0]--;
4376 }
4377 leaf = path->nodes[0];
4378 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4379 btrfs_release_path(path);
4380
4381 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4382 key.type != BTRFS_ROOT_ITEM_KEY)
4383 break;
4384
4385 reloc_root = btrfs_read_fs_root(root, &key);
4386 if (IS_ERR(reloc_root)) {
4387 err = PTR_ERR(reloc_root);
4388 goto out;
4389 }
4390
4391 list_add(&reloc_root->root_list, &reloc_roots);
4392
4393 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4394 fs_root = read_fs_root(root->fs_info,
4395 reloc_root->root_key.offset);
4396 if (IS_ERR(fs_root)) {
4397 ret = PTR_ERR(fs_root);
4398 if (ret != -ENOENT) {
4399 err = ret;
4400 goto out;
4401 }
4402 ret = mark_garbage_root(reloc_root);
4403 if (ret < 0) {
4404 err = ret;
4405 goto out;
4406 }
4407 }
4408 }
4409
4410 if (key.offset == 0)
4411 break;
4412
4413 key.offset--;
4414 }
4415 btrfs_release_path(path);
4416
4417 if (list_empty(&reloc_roots))
4418 goto out;
4419
4420 rc = alloc_reloc_control(root->fs_info);
4421 if (!rc) {
4422 err = -ENOMEM;
4423 goto out;
4424 }
4425
4426 rc->extent_root = root->fs_info->extent_root;
4427
4428 set_reloc_control(rc);
4429
4430 trans = btrfs_join_transaction(rc->extent_root);
4431 if (IS_ERR(trans)) {
4432 unset_reloc_control(rc);
4433 err = PTR_ERR(trans);
4434 goto out_free;
4435 }
4436
4437 rc->merge_reloc_tree = 1;
4438
4439 while (!list_empty(&reloc_roots)) {
4440 reloc_root = list_entry(reloc_roots.next,
4441 struct btrfs_root, root_list);
4442 list_del(&reloc_root->root_list);
4443
4444 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4445 list_add_tail(&reloc_root->root_list,
4446 &rc->reloc_roots);
4447 continue;
4448 }
4449
4450 fs_root = read_fs_root(root->fs_info,
4451 reloc_root->root_key.offset);
4452 if (IS_ERR(fs_root)) {
4453 err = PTR_ERR(fs_root);
4454 goto out_free;
4455 }
4456
4457 err = __add_reloc_root(reloc_root);
4458 BUG_ON(err < 0); /* -ENOMEM or logic error */
4459 fs_root->reloc_root = reloc_root;
4460 }
4461
4462 err = btrfs_commit_transaction(trans, rc->extent_root);
4463 if (err)
4464 goto out_free;
4465
4466 merge_reloc_roots(rc);
4467
4468 unset_reloc_control(rc);
4469
4470 trans = btrfs_join_transaction(rc->extent_root);
4471 if (IS_ERR(trans))
4472 err = PTR_ERR(trans);
4473 else
4474 err = btrfs_commit_transaction(trans, rc->extent_root);
4475 out_free:
4476 kfree(rc);
4477 out:
4478 if (!list_empty(&reloc_roots))
4479 free_reloc_roots(&reloc_roots);
4480
4481 btrfs_free_path(path);
4482
4483 if (err == 0) {
4484 /* cleanup orphan inode in data relocation tree */
4485 fs_root = read_fs_root(root->fs_info,
4486 BTRFS_DATA_RELOC_TREE_OBJECTID);
4487 if (IS_ERR(fs_root))
4488 err = PTR_ERR(fs_root);
4489 else
4490 err = btrfs_orphan_cleanup(fs_root);
4491 }
4492 return err;
4493 }
4494
4495 /*
4496 * helper to add ordered checksum for data relocation.
4497 *
4498 * cloning checksum properly handles the nodatasum extents.
4499 * it also saves CPU time to re-calculate the checksum.
4500 */
4501 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4502 {
4503 struct btrfs_ordered_sum *sums;
4504 struct btrfs_ordered_extent *ordered;
4505 struct btrfs_root *root = BTRFS_I(inode)->root;
4506 int ret;
4507 u64 disk_bytenr;
4508 u64 new_bytenr;
4509 LIST_HEAD(list);
4510
4511 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4512 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4513
4514 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4515 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4516 disk_bytenr + len - 1, &list, 0);
4517 if (ret)
4518 goto out;
4519
4520 while (!list_empty(&list)) {
4521 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4522 list_del_init(&sums->list);
4523
4524 /*
4525 * We need to offset the new_bytenr based on where the csum is.
4526 * We need to do this because we will read in entire prealloc
4527 * extents but we may have written to say the middle of the
4528 * prealloc extent, so we need to make sure the csum goes with
4529 * the right disk offset.
4530 *
4531 * We can do this because the data reloc inode refers strictly
4532 * to the on disk bytes, so we don't have to worry about
4533 * disk_len vs real len like with real inodes since it's all
4534 * disk length.
4535 */
4536 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4537 sums->bytenr = new_bytenr;
4538
4539 btrfs_add_ordered_sum(inode, ordered, sums);
4540 }
4541 out:
4542 btrfs_put_ordered_extent(ordered);
4543 return ret;
4544 }
4545
4546 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4547 struct btrfs_root *root, struct extent_buffer *buf,
4548 struct extent_buffer *cow)
4549 {
4550 struct reloc_control *rc;
4551 struct backref_node *node;
4552 int first_cow = 0;
4553 int level;
4554 int ret = 0;
4555
4556 rc = root->fs_info->reloc_ctl;
4557 if (!rc)
4558 return 0;
4559
4560 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4561 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4562
4563 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4564 if (buf == root->node)
4565 __update_reloc_root(root, cow->start);
4566 }
4567
4568 level = btrfs_header_level(buf);
4569 if (btrfs_header_generation(buf) <=
4570 btrfs_root_last_snapshot(&root->root_item))
4571 first_cow = 1;
4572
4573 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4574 rc->create_reloc_tree) {
4575 WARN_ON(!first_cow && level == 0);
4576
4577 node = rc->backref_cache.path[level];
4578 BUG_ON(node->bytenr != buf->start &&
4579 node->new_bytenr != buf->start);
4580
4581 drop_node_buffer(node);
4582 extent_buffer_get(cow);
4583 node->eb = cow;
4584 node->new_bytenr = cow->start;
4585
4586 if (!node->pending) {
4587 list_move_tail(&node->list,
4588 &rc->backref_cache.pending[level]);
4589 node->pending = 1;
4590 }
4591
4592 if (first_cow)
4593 __mark_block_processed(rc, node);
4594
4595 if (first_cow && level > 0)
4596 rc->nodes_relocated += buf->len;
4597 }
4598
4599 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4600 ret = replace_file_extents(trans, rc, root, cow);
4601 return ret;
4602 }
4603
4604 /*
4605 * called before creating snapshot. it calculates metadata reservation
4606 * required for relocating tree blocks in the snapshot
4607 */
4608 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4609 u64 *bytes_to_reserve)
4610 {
4611 struct btrfs_root *root;
4612 struct reloc_control *rc;
4613
4614 root = pending->root;
4615 if (!root->reloc_root)
4616 return;
4617
4618 rc = root->fs_info->reloc_ctl;
4619 if (!rc->merge_reloc_tree)
4620 return;
4621
4622 root = root->reloc_root;
4623 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4624 /*
4625 * relocation is in the stage of merging trees. the space
4626 * used by merging a reloc tree is twice the size of
4627 * relocated tree nodes in the worst case. half for cowing
4628 * the reloc tree, half for cowing the fs tree. the space
4629 * used by cowing the reloc tree will be freed after the
4630 * tree is dropped. if we create snapshot, cowing the fs
4631 * tree may use more space than it frees. so we need
4632 * reserve extra space.
4633 */
4634 *bytes_to_reserve += rc->nodes_relocated;
4635 }
4636
4637 /*
4638 * called after snapshot is created. migrate block reservation
4639 * and create reloc root for the newly created snapshot
4640 */
4641 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4642 struct btrfs_pending_snapshot *pending)
4643 {
4644 struct btrfs_root *root = pending->root;
4645 struct btrfs_root *reloc_root;
4646 struct btrfs_root *new_root;
4647 struct reloc_control *rc;
4648 int ret;
4649
4650 if (!root->reloc_root)
4651 return 0;
4652
4653 rc = root->fs_info->reloc_ctl;
4654 rc->merging_rsv_size += rc->nodes_relocated;
4655
4656 if (rc->merge_reloc_tree) {
4657 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4658 rc->block_rsv,
4659 rc->nodes_relocated, 1);
4660 if (ret)
4661 return ret;
4662 }
4663
4664 new_root = pending->snap;
4665 reloc_root = create_reloc_root(trans, root->reloc_root,
4666 new_root->root_key.objectid);
4667 if (IS_ERR(reloc_root))
4668 return PTR_ERR(reloc_root);
4669
4670 ret = __add_reloc_root(reloc_root);
4671 BUG_ON(ret < 0);
4672 new_root->reloc_root = reloc_root;
4673
4674 if (rc->create_reloc_tree)
4675 ret = clone_backref_node(trans, rc, root, reloc_root);
4676 return ret;
4677 }
Linux kernel - Deliverables
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